Monday, November 30, 2009

A Historic Paper on Cuckoo Behavior

In the coming year, the Royal Society is entering its 350th year of existence. It was founded on November 28, 1660, as a forum for scientists and philosophers to discuss their work. Since 1665, it has published the journal Philosophical Transactions. To celebrate its anniversary, the Royal Society is posting sixty of the most significant papers from Philosophical Transactions. You can find them at the society's Trailblazing website.

Common Cuckoo (Source: Naumann, Naturgeschichte der Vögel Mitteleuropas)

Nestled among the other historic papers is one that concerns birds. In 1788, Edward Jenner reported his observations of Common Cuckoos (Cuculus canorus). Common Cuckoos, like several other species, are nest parasites. This means that, rather than building and incubating its own nest, an adult female will lay its eggs in the nests of other bird species. A bird of a different species will then be responsible for the incubation and rearing of the young cuckoo. Brown-headed Cowbirds are a well-known example of this breeding behavior in North America.

According to Jenner's paper, he observed cuckoos laying eggs in the nests of "the Hedge-sparrow, the Water-wagtail, the Titlark, the Yellowhammer, the green Linnet, and the Whinchat." Of these, he most frequently saw cuckoos using the nests of the Hedge-sparrow, which I believe is now called Dunnock (Prunella modularis). In most cases, the offspring of the foster parent would be thrown out of the nest, while only the cuckoo chick remained for feeding.

On June 19, 1787, Jenner watched a cuckoo chick expel one of its nest mates:
The mode of accomplishing this was very curious. The little animal, with the assistance of its rump and wings, contrived to get the bird upon its back, and making a lodgement for the burden by elevating its elbows, clambered backward with it up the side of the nest till it reached the top, where resting for a moment, it threw off its load with a jerk, and quite disengaged it from the nest. It remained in this situation a short time, feeling about with the extremities of its wings, as if to be convinced that the business was properly executed, and then dropped into the nest again. With these (the extremities of its wings) I have often seen it examine, as it were, an egg and nestling before it began its operations; and the nice sensibility which these parts appeared to possess seemed sufficiently to compensate the loss of sight, which as yet it was destitute of. I afterwards put in an egg, and this, by a similar process, was conveyed to the edge of the nest, and thrown out. These experiments I have since repeated several times in different nests, and have always found the young Cuckoo disposed to act in the same manner.
The body of the cuckoo chick is suited to expelling other chicks:
The singularity of its shape is well adapted to these purposes; for, different from other newly-hatched birds, its back from the scapulae downwards is very broad, with a considerable depression in the middle. This depression seems formed by nature for the design of giving a more secure lodgement to the egg of the Hedge-sparrow, or its young one, when the young Cuckoo is employed in removing either of them from the nest. When it is about twelve days old, this cavity is quite filled up, and then the back assumes the shape of nestling birds in general.
On occasion, an adult bird might expel one of its own eggs to make room for the cuckoo egg, but once the eggs were hatched the adult cared for all equally, provided that they remained in the nest. If two cuckoo eggs happened to be laid in the same nest, the two young cuckoos would struggle for control of the nest.

Jenner explains the cuckoo's parasitism by referencing the short time cuckoos have to reproduce. Adults arrive in Britain in mid-April, begin laying in mid-May, and depart in early July. Laying eggs in the nests of other bird species allows cuckoos to maintain a large population despite this short breeding season.

Reading this paper was a look not just at cuckoos but at the scientific culture of Jenner's day. Like other naturalists of his day, he readily shot birds to confirm identification or examine them. He also collected eggs and received eggs from others. Both of those activities would require permits today, at least in the United States. This paper was written long before Origin of Species, and the lack of a concept of natural selection is evident in several passages, including the second one above. Instead, Jenner refers several times to nature's design, a concept that he does not have much elaboration.
Jenner, E. (1788). Observations on the Natural History of the Cuckoo. By Mr. Edward Jenner. In a Letter to John Hunter, Esq. F. R. S. Philosophical Transactions of the Royal Society of London (1776-1886), 78 (1), 219-237 DOI: 10.1098/rstl.1788.0016

Sunday, November 29, 2009

Late Fall Dragonflies

I photographed this Autumn Meadowhawk near the Passaic River in Lord Stirling Park yesterday. It was one of about a dozen or more meadowhawks that I observed. Autumn Meadowhawks are one of the few odonate species still flying this late in the year. NJ Odonata Survey lists their late date as December 8.

Earlier in the week, I saw both Autumn Meadowhawks and Common Green Darners flying at Rutgers Gardens.

But Can We Eat It Elsewhere?

epic fail pictures
see more Epic Fails

Actually, I can't imagine why someone would want to eat a gull in the first place. Birds that prey on marine organisms tend to have an unpleasant, fishy taste. This ought to apply as much to gulls as it does to cormorants or sea ducks.

Also, as a birder I am obliged to note that there many species of gull, with a variety of names, but there is no bird called a "seagull." Of course, there is such a thing as a Seagull.


Saturday, November 28, 2009

Lord Stirling Park and Great Swamp Hunting Dates

This post will be primarily of interest to Jersey birders. Great Swamp NWR and Lord Stirling Park usually have a series of closures throughout the fall. The closures are to keep other potential visitors safe while hunters cull some of the white-tailed deer that roam the adjacent preserves.

Unfortunately for birders, the dates and places of hunting closures, as well as regulations governing the season, can be confusing, even if they are readily findable. Since I was at Lord Stirling Park today, I am posting the list of closures for that site here. Hunting season has ended at Great Swamp NWR, but there are still some dates left at Lord Stirling Park for 2009.

I don't object to hunting on public lands, even in places where I like to visit. However, I wish information about when and where hunts are taking place were more readily available in a form more understandable to non-hunters. Since the state does not seem interested in communicating this to non-hunters, perhaps there is room for a birding or hiking organization to fill the gap.

Golden Eagle Killing Goats

Golden Eagles are powerful hunters. Unlike Bald Eagles, which primarily hunt fish and often scavenge, Golden Eagles will take a variety of mammals and land birds. Last night, Lady Woodpecker tweeted this video of a Golden Eagle taking down a young goat.

There seem to be at least two different hunts combined in this video with the first and third segments showing the same hunt from different angles.

Friday, November 27, 2009

Loose Feathers #214

Bird and birding news
Birds in the blogosphere
Environment and biodiversity

Thursday, November 26, 2009

SkyWatch: Magnolia

This is a magnolia tree; I am not sure of the species. The principle magnolia found in the wild in New Jersey is probably Sweetbay Magnolia, which this tree is not. Instead I think it may be a Cucumbertree, one of the taller magnolia species.

While branches near the top reached for the sky, this tree's lower branches arched downwards in graceful curves.

What tipped me off to the tree's family were the large buds, which are fairly distinctive. This tree is already preparing for spring.

Trees in the magnolia family are unusual among deciduous trees in having tough, waxy leaves. In northern regions, these leaves turn brown and drop in the fall. In southern regions, some species may stay evergreen through the winter.

Sexing Turkeys with Spectroscopy

A new study finds a way to identify the sex of turkey poults before they have developed visible sex differences.
Numerous bird species, nestlings and immature birds in particular, lack external sexual characteristics. Knowledge of a bird's gender is important for poultry breeders, veterinary practitioners, aviculturists and ornithologists. For example, accurate determination of a bird's gender is essential for proper pairing of birds, and knowing the gender of a bird allows veterinarians to diagnose gender-specific diseases. Equally, the poultry industry is interested in fast, objective and inexpensive methods for determining the sex of chickens and turkeys as early as possible -- their interest lying mainly in the egg-producing female.

Dr. Steiner and his team applied infrared spectroscopic imaging to determine the gender of turkey poults. They looked at pulp germ cells extracted from the growing contour feathers of 23 male and 23 female six-week-old turkey poults. This technique provides direct access to the birds' gender as the classification is based on the genetic information contained in the cells. Their method successfully classified female and male poults with an accuracy of more than 95 percent.
Here is the full journal article.

The main application for this research seems to be the poultry industry, which prefers to breed female poultry for egg-laying. The same spectroscopic techniques used to analyze feather pulp could also analyze unhatched but fertilized eggs, as well as distinguish fertilized from unfertilized eggs. The press release describes the research as preventing "millions of male chicks from being killed shortly after birth." The alternative is unstated but presumably means separating out male eggs and discarding them before they hatch.

Beyond the poultry industry, it possible that this technique could be useful for captive breeding programs, though I am not sure such breeders would be as concerned about the sex of a bird before it has hatched. Of course, such programs could use it to avoid wasting time and resources to incubate unfertilized eggs.

Wednesday, November 25, 2009

How Raptor Talons Fit Their Prey

Most birders learn through field guides that different raptor groups have recognizable body shapes adapted to the way they hunt. Accipiters, for example, have short rounded wings and long tails to facilitate short pursuits through close quarters. This is, in fact, a key to identifying many raptors in the field. Close study of raptors reveals even more subtle anatomical differences. A newly published article in PLoS ONE relates differences in the shapes of raptor talons to how they kill their prey.

The first thing to understand is that raptors do not usually kill their prey by wounding them with their talons or beaks. Instead, most raptors kill their prey by constriction – squeezing their prey so tightly that death comes by asphyxiation. In a minority of cases, this squeezing motion may cause fatal injury if a talon pierces a vital organ. In other cases, a raptor may start dismembering and eating its prey before the prey is fully dead. In addition, falcons may attempt to break the spinal cords of their prey using a special tooth-like projection on their beaks. Here is an example of such a "tooth" on a Peregrine Falcon. The Merlin at right has another such "tooth." To my knowledge, no buteo or accipiter has such a feature.

Given the prominent role that a raptor's feet play in seizing prey, it makes sense that the shape of their feet might vary with how a raptor uses them. This is in fact the result reached by a team of graduate students after they photographed and measured the feet of hundreds of bird specimens, both raptors and non-raptors. (Most specimens were held by Montana State University; others were from the American Museum of Natural History.) The most significant differences in claw shape were among raptor families and distinguished raptors from non-raptors.

Figure 1. Feet of representative raptors. (A) Accipitridae: goshawk; (B), Accipitridae: red-tailed hawk; (C) Falconidae: peregrine falcon; (D) Strigiformes: great grey owl; (E) Pandionidae: osprey. Source: PLoS ONE.

Here are the significant characteristics of each raptor family:
  • Accipitridae (including accipiters, buteos, and eagles) have first and second talons (D-I and D-II) that are exceptionally large in proportion to their other talons.
  • Falconidae have talons that are more equal in size than Accipitridae but D-I and D-II continue to be proportionately larger.
  • Strigiformes have large talons that are more equal in size mounted on short strong toes.
  • Pandionidae have long and exceptionally curved talons. The largest talon, D-IV, can rotate so that an osprey can grip its prey with two talons on one side and two on the other.
Having a D-II talon that is similar in size or larger than a D-III talon separates all raptor families from non-raptors, which have a significantly larger D-III.

Table 1. Mean and standard deviation of claw sizes (outer arc lengths) of D-I, II, and III relative to D-IV, and D-II relative to D-III. Source: PLoS ONE.

The authors argue that the best explanation for the variation in talon proportions is hunting technique. Falcons can afford to have proportionately shorter talons since they strike their prey at high speed while airborne; this strike is often sufficient to kill or seriously injure their prey. If not, they have the option of using their false tooth to break the neck of their prey. Owls have short toes and long talons that give them maximum leverage to constrict small prey. Accipitrids, by contrast, have neither the powerful feet of owls nor the high-speed hunting techniques of falcons. Instead, they can either constrict small prey or use their longer first and second talons to their advantage against larger prey. These long talons allow them to grip large prey even as the prey struggles to escape. Once the prey is subdued, the hawk can begin plucking and eating, regardless of whether the prey is dead. Foot shape gives Accipitrid hawks more options for what they can capture and eat.
Fowler, D., Freedman, E., & Scannella, J. (2009). Predatory Functional Morphology in Raptors: Interdigital Variation in Talon Size Is Related to Prey Restraint and Immobilisation Technique PLoS ONE, 4 (11) DOI: 10.1371/journal.pone.0007999

Tuesday, November 24, 2009

150 Years of Evolutionary Theory

On this day in 1859, Charles Darwin's On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life was published for the first time. Even before Darwin's work, other scientists had speculated that existing species could be transformed into other species. Darwin drew from these concepts, but he advanced the idea that species are continually adapting in response to natural selection. Despite its vilification by creationists, evolution by natural selection remains the guiding concept of the biological sciences. Many bloggers are more qualified than I to discuss the implications of Darwin's work and how evolutionary theory has developed since 1859, so I will leave more detailed discussions to them.

Birders, however, should celebrate this anniversary as we are in a particularly strong position to appreciate the results of evolution. We do not necessarily think consciously about evolution when we go birding; in my own experience, I think about Darwin very rarely while I have binoculars around my neck. But among birds, we can observe the diversity of forms and behaviors produced by natural selection. Warbler species, for example, evolved to fill many specific ecological niches. One warbler species forages mainly among dead leaf clusters; another breeds only in jack pine forests of a certain age; yet another warbler with bark-like black-and-white streaking specializes in picking invertebrates off the trunks and limbs of trees. Whether we realize it consciously or not, these evolutionary adaptations help us to identify birds. That buzzy, insect-like call is likely to mean different sparrow species in a grassy field and a saltmarsh; the same goes for a trilled song heard in a swamp and a suburb. Without some awareness of these species' adaptations to ecological conditions, birding by ear and birding by GISS would be a lot more difficult.

Since On the Origin of Species is old enough to be in the public domain, there are many complete digital copies of this book available online. Try, TalkOrigins, Bartleby, or Project Gutenberg if you want to read it.

For other evolution-related reading on this blog, see my review of Pilgrim on the Great Bird Continent, an article on the evolution of wood warblers, the announcement of a new crossbill species in Idaho, an analysis of the evolution of waterfowl genitals, and a more recent post on new research into birds of the Galápagos.

Monday, November 23, 2009

A Washed-up Skate

At the second site we visited during Saturday's trip to Barnegat Inlet, there was a skate washed up on the beach. The tracks and dropping around the skate indicate that some birds had already discovered the skate's remains. The skate has a bloody patch on its right side, presumably from scavengers picking at it. While some openings on this skate are probably natural (the eyes and mouth need openings), others are more likely the work of scavengers. I am not entirely sure which holes fit in which category.

The photo above is a close-up of the skate's nose, eyes, and mouth.

Another point that I am not sure about is which species of skate was on the beach. There are six species of skate present in the Atlantic off the northeastern United States. Its translucent head suggests that this may be a Clearnose Skate, but I am not certain that this feature is diagnostic, especially for an animal that is getting picked on. Clearnose Skate is a southern species; according to the NOAA site New Jersey is at the northern end of this animal's range.

I did not realize this at the time, but it is possible to imagine a human face in the skate's remains if you view them from a certain perspective.

Added to Macro Monday.

Sunday, November 22, 2009

Birds at Barnegat Inlet

Yesterday morning I went with my parents and sister to meet up with my uncle and his wife at Barnegat Lighthouse State Park. During winter months, this site offers some of the best coastal birding in the state. One of its major advantages as a birding site is that it allows relatively close approach. Birds that winter there seem used to being around large numbers of people and tend not to flush as quickly as at other sites. This allows close viewing of birds that we do not see very often.

It is the most reliable site in the state for finding northern waterfowl such as Common Eiders and Harlequin Ducks. Both of these species, as well as scoters, were present in modete numbers yesterday. I only saw one Harlequin Duck myself, but there was a larger flock farther down the beach. Other wintering waterfowl such as Long-tailed Ducks and Buffleheads were nowhere near their winter peak numbers. In addition to the headline ducks, there was a flock of Brant next to the jetty.

Several shorebird species were present along the jetty. A small flock of Black-bellied Plovers were hiding in the beach grass. Flocks of American Oystercatchers flew past us over in the inlet. On the jetty itself, there were Ruddy Turnstones, Dunlin, and Purple Sandpipers. The largest group of shorebirds that I noted was a flock of Dunlin numbering around 100. Above is a Dunlin and a Ruddy Turnstone loafing on the same rock. I posted other photos of Dunlin and Turnstones at my Flickr account.

Gulls, though abundant, should not be neglected. This handsome immature Herring Gull started its long call just as I took its photograph.

Walking from the lighthouse to the far end of the jetty is always exciting. I am lured farther and farther out by the prospect or seeing new birds or having a better view of birds I have seen distantly or in poor light. Plus there are constantly new birds – sandpipers, sparrows, etc. – popping up from between the jetty's rocks. On the way back I am more tired, more worried about my footing, and have seen most of the bird species the jetty has to offer. At least the return trip offers a marvelous view:

In the afternoon we walked along the "High Bar" beach to the west of the lighthouse. Most of the birds were the same as at the jetty – small flocks of Brant, Black-bellied Plovers, and Dunlin, with a few other water birds in the mix. One new addition was a hatch-year Merlin perched at the top of a bare tree. Not bad at all for a fall day!

Saturday, November 21, 2009

Christmas Bird Counts Coming Soon!

The first of this year's Christmas Bird Counts are less than a month away. The counts will run from Monday, December 14th, to Tuesday, January 5th. Most will occur on the weekends of December 19-20th and 26-27th, with a few clustered around New Year's Day.

Christmas Bird Counts give birders the opportunity to participate in a long-running citizen science project. By late December, most migratory birds have settled into their winter ranges. CBCs provide observational data to assess where those ranges are, how big the winter populations are, and whether there are any changes over the years. Most counts have been running for a few decades; some have been running for much longer.

You can find a schedule for New Jersey's CBCs here. Similar schedules may be available for other states or regions. You can also find the times and locations for CBCs in other areas at the National Audubon Society site. This year, I will be participating in at least two counts in New Jersey.

Friday, November 20, 2009

Loose Feathers #213

Bird and birding news
Birds in the blogosphere
Environment and biodiversity
Carnivals and newsletters

Thursday, November 19, 2009

SkyWatch: Black and White Reflections

Sometimes it helps to look down if you want to see the sky. Here is the color version.

These photos were taken in the Princeton Institute Woods. Stony Brook, the stream in the images, is crossed by a narrow footbridge that connects to the D&R Canal. The bridge is labeled a "swing bridge" on trail maps, but there does not seem to be any swing mechanism involved. However, it does bounce as you walk across.

Two New eBird Projects

At the end of last week, eBird announced two projects designed to improve the quality of its database. The first, and most important for continental and regional range information, is the County Birding Project. One problem with the current eBird database is that some counties, especially ones near metropolitan areas, get strong coverage from birders while other counties are barely covered at all. Within counties, population centers are often well-covered while outlying areas are not. There are suggestions at the link for surveys to improve county coverage, both within counties and regionally.

To assist in the project, eBird added a new checklist type for random location counts. Random locations are locations at fixed intervals along a driving (or cycling) route.

The county birding announcement links to a spreadsheet with county checklist totals from across the country. As one might expect, few counties in New Jersey are lacking in checklists. The county with the lowest number of checklists, Salem, has 449. The next lowest is Warren, with 949. Even nearby states are pretty well covered compared to other areas of the country. For example, South Dakota has 22 counties in single digits. Also, Nate's Century Club could fill some gaps.

The second announcement was for a Site Survey Project. This concept is not all that new, since eBird has long encouraged users to bird the same locations regularly to compile the most useful data. The new part is that users can register sites where they expect to bird at least once per week and participate in a discussion group about site surveys.

Wednesday, November 18, 2009

Darwin's Birds: Evolution and DNA in the Galápagos

Whether by chance or by design, this week witnessed the publication of two studies on birds from the islands made famous by Charles Darwin. The first concerns one of the best-known examples of evolution, the Galápagos finches. A married pair of biologists have been banding and tracking finches on Daphne Major for several decades. In 1981, they banded a medium ground-finch (Geospiza fortis) that was significantly larger than most other medium ground-finches on the island. Since then, its descendants, which have unusual beaks and songs, have stopped breeding with other medium ground-finches.
The fact that 5110's descendants haven't mixed could be because they differ from the natives. The Grants note that the descendants have a differently shaped beak from those native to Daphne Major. As finch beaks are vital in identifying potential mates, this could serve to keep them reproductively isolated.

5110's offspring also have the avian equivalent of a strange accent. These finches learn their songs from their father, and the Grants suggest that 5110 sang the songs from his birth home of Santa Cruz then modified his come-hither ballad by roughly copying the Daphne Major birds'. This imperfect copying, they suggest, has over time acted as a barrier to interbreeding.

Lukas Keller of the Zoological Museum at the University of Zurich, Switzerland, agrees that 5110's case is special. However, he thinks it may be possible to generalize to other species who learn behaviours such as singing in a similar way. "For me it's a very exciting paper," he says.

Whereas Darwin thought that a new species would take a considerable amount of time to appear, Keller says that this paper "shows how rapidly reproductive isolation can develop".
It is not yet clear that this is a new species, even though some headlines give that impression. However, it does provide a real-time view of how reproductive isolation and speciation can begin.

The second study reports on the feasibility of introducing a rare mockingbird into part of its former range. Darwin and his colleagues had collected specimens of the Floreana mockingbird (Mimus trifasciatus) from Floreana Island, part of the Galápagos archipelago. Due to human interference, the mockingbird became extinct on Floreana but survived on nearby islands. The Charles Darwin Foundation wants to bring the Floreana mockingbird back to Floreana. Before attempting to do so, they compared DNA samples from the remaining subpopulations to that of specimens collected by Darwin.
This revealed that the two sub-populations split from each other very recently. This split, the researchers said, was likely caused by the Floreana mockingbird becoming extinct.

Its extinction would have severed a "bridge" between the two populations - meaning that it was no longer possible for them to interbreed.

Even though they have evolved independently and become inbred, this study showed that the tiny sub-populations have retained much of the important "genetic variation" once found in the mockingbirds on Floreana.

This is good news for the survival of the species.

It has led the researchers to conclude that future conservation plans should focus on protecting "the two satellite populations in situ and establishing a single third population on Floreana".

This reintroduction could use birds from both islands, the researchers said, "to maximize genetic diversity".
I suppose one remaining question is whether the mockingbirds from these subpopulations will be inclined to interbreed after being separated for so long. That issue is not addressed in the BBC article, but the scientists seem confident enough that it may not actually be a problem.

Aside being fascinating examples of biodiversity in action, these two studies highlight the continued usefulness of bird research techniques that may seem dated. The mockingbird study showed the importance of museum collections as repositories of physical evidence for future generations of ornithologists. In this case, it provided DNA evidence for a study of subpopulations, a use that probably was not imagined by Darwin and his companions when they collected the specimens. The study of ground finches relied on bird banding to identify and track individual birds.

Tuesday, November 17, 2009

A Moth and Me (and a Few Birds)

The November edition of The Moth and Me was just posted yesterday. This is the last edition for 2009 since moths in northern latitudes are becoming less and less active. The next edition will be in March of 2010.

Since I am posting a moth-related carnival, I will use this as an excuse to post a recent moth photo, taken at Negri-Nepote Grasslands Preserve on Sunday.

This is not the best of photos, but I believe this moth is still identifiable as a Celery Leaftier (Udea rubigalis). These moths are very small and flit around in the grass. A few other moths were also active at the preserve, but I was not able to photograph or identify them by sight.

The preserve was well-stocked with sparrows of multiple species. White-throated and Song Sparrows were, of  course, in large numbers. A few Field Sparrows and a lingering Chipping Sparrow were also present. The most noticeable birds, however, were the Savannah Sparrows, which almost outnumbered much more common species. At one location, a half-dozen put on a show for me as they hopped around and splashed in a shallow puddle. I also saw a Vesper Sparrow, which did not seem to be on good terms with the Savannahs.

Even though it was Sunday, gunners were firing in a nearby field (presumably private property). They were far enough away not to pose a significant threat, but close enough to be unnerving. Apparently crows liked their activity even less. A large mass of crows – over 200 – converged on that field and noisily mobbed whoever was shooting.

Monday, November 16, 2009

Birds' Color Vision Fades With Daylight

Birds are known to have extraordinary color vision during the day. Among other things, this ability helps them to distinguish among the dazzling array of avian plumages. New research shows that birds' color vision vanishes at dusk.
For humans and horses, color vision ceases to work after dusk, at light intensities roughly corresponding to bright moonlight. However, the light threshold is not the same for all vertebrates. Geckos, for instance, can see colors at night. In the experiments performed by the Lund University Vision Group, the color vision of birds stopped working at light intensities corresponding to what prevails shortly after the sun goes down. Birds need between 5 and 20 times as much light as humans to see colors. Among all the vertebrates tested thus far, birds are the first to lose their color vision in the twilight, even though they are the vertebrates that probably see colors best of all in the daylight.

With these findings it is now possible to start to draw conclusions about how birds use their color vision at dawn and dusk. The findings also direct our focus to previous research about how important color is when it comes to eggs or begging baby birds in enclosed nests. Inside enclosed nests it is dark even when the sun is bright outside.

"Against the background of our new discoveries, we should now re-evaluate earlier research about how birds perceive the color of their eggs and their young in the nest," says Olle Lind.
This conclusion is interesting in its own right. I wonder if it might also have some application to other questions about bird behavior. During migration, birds fly at night, a task that requires both an aerodynamic body and special navigation skills. Conventional wisdom at the moment indicates that birds navigate using a combination of the Earth's magnetic field and the stars. Would lack of color vision have any bearing on navigation? Second, there remains the problem of birds colliding into windows and other man-made structures. Could this be caused in part by the lack of color vision in dark or dim lighting conditions? Perhaps this finding could inspire new ways to prevent such fatal collisions.

Sunday, November 15, 2009

SkyWatch Robin

I took this photo while the skies were somber at the end of last week. With persistent rain and wind spread over several days, the chances for birding were pretty brief, so I tried to make the most of them. This American Robin sat still as I approached; it seemed preoccupied with swallowing or regurgitating something.

Runoff and Intersex Fish in the Potomac

Source: Washington Post

The Potomac Conservancy reports that runoff is causing the intersex fish problem.
The report says it appears that chemicals -- it's still not certain which ones -- in the water are interfering with the hormones that guide development in the fish. It said that potential causes include animal hormones from manure washing off farm fields in the rain and human hormones and pharmaceuticals that are flushed out with treated sewage.

It seems likely, the report said, that the cause is not a single chemical but a mixture whose components might be different around the river. Pesticides might dominate in rural areas, for instance, and human hormones downstream of a sewage plant.

Hedrick Belin, the conservancy's president, said that the best solution to the problem was to try to keep these chemicals out of the water in the first place. That, he said, could entail increased testing to figure out which chemicals have hormone-mimicking properties or installing measures to keep animal waste from washing downstream.
You can read the full report for 2009 at the Potomac Conservancy's website.

Sources of Endocrine Disruptors / Source: Potomac Conservancy

The Potomac Conservancy says that they do not know what effect of these pollutants have on human health. I am not sure how closely the effects on humans have been studied; if anyone knows, I would be happy to find out. In the meantime, I think it is better to err on the safe side and reduce the flow of chemicals that disrupt hormones into runoff. Working to reduce those may have the happy side effect of reducing the introduction of other harmful pollutants into the Chesapeake watershed as well.

Saturday, November 14, 2009

Why Use Flickr? One Example of Its Advanges in Action

Some time ago, Mike Bergin asked why and how a blogger would use Flickr for image hosting. The thread generated many interesting responses, some favorable and some not. Participants cited a variety of reasons for using the service. A few expressed frustration with its limitations.

For me, it comes down to four basic reasons. First, titles, tags, descriptions, and sets make it easy to retrieve older but still useful photos – much easier than on my computer. Second, it provides a space to post photos of subjects that would be off-topic on my blog but that I would still like to share with others. (For example, it is hard to write a nature blog post around photos like these.) Third, the Flickr community (or more accurately communities) can be a source of encouragement and feedback. Groups make it easy to find other users with similar interests, even fairly arcane ones. Fourth, many Flickr users (as I do) post their photos under a Creative Commons license. This provides a rich source of images that can be used with blog posts; many of the photos in recent Loose Feathers editions have come from Flickr.

I experienced an example of the third advantage last weekend. I was having trouble identifying a moth from an older photo, shown below. Within a few hours of my posting it to Flickr, a few of my contacts responded with helpful suggestions, one of which nailed the identification as a Maple Looper (Parallelia bistriaris).

Chances are that even without Flickr, I would have had an accurate identification eventually anyway. Over time, I have developed contacts through the blogosphere and Twitter who are knowledgeable about insects in general and moths in particular. But, like the blogosphere, Flickr has the means to link people with similar interests who live in disparate locations. It is to the advantage of nature bloggers to participate in these communities where they exist.

Friday, November 13, 2009

Loose Feathers #212

Bird news
Birds in the blogosphere
Environment and biodiversity
Carnivals and newsletters

Thursday, November 12, 2009

I and the Bird

Matthew Sarver posted I and the Bird #113 at his blog.

Brown Pelican Delisted

Yesterday, the Interior Department announced that Brown Pelicans have recovered and would no longer be protected as an endangered or threatened species. Its decline was caused by a combination of habitat loss and the widespread use of DDT. In the early years of the 20th century, it was hunted.
The brown pelican was first declared endangered in 1970 under the Endangered Species Preservation Act, a precursor to the current Endangered Species Act. Since then, thanks to a ban on DDT and efforts by states, conservation organizations, private citizens and many other partners, the bird has recovered. There are now more than 650,000 brown pelicans found across Florida and the Gulf and Pacific Coasts, as well as in the Caribbean and Latin America.

The Fish and Wildlife Service removed the brown pelican population in Alabama, Georgia, Florida, and northward along the Atlantic Coast states from the list of endangered species in 1985. Today’s action removes the remaining population from the list....

Past efforts to protect the brown pelican actually led to the birth of the National Wildlife Refuge System more than a century ago in central Florida. German immigrant Paul Kroegel, appalled by the indiscriminate slaughter of pelicans for their feathers, approached President Theodore Roosevelt. This led Roosevelt to create the first National Wildlife Refuge at Pelican Island in 1903, when Kroegel was named the first refuge manager. Today, the system has grown to 550 national wildlife refuges, many of which have played key roles in the recovery of the brown pelican.

With removal of the brown pelican from the list of threatened and endangered species, federal agencies will no longer be required to consult with the Service to ensure any action they authorize, fund, or carry out will not harm the species. However, additional federal laws, such as the Migratory Bird Treaty Act and the Lacey Act, will continue to protect the brown pelican, its nests and its eggs.
It is encouraging to see endangered species recover and move off the endangered species list. There have been a few high-profile removals of recovered species over the past decade or so – peregrine falcon and bald eagle come to mind. However, there have also been a few in which delisting was premature. The travails of gray wolves since their delisting have been particularly saddening. I hope that the future of brown pelicans has more in common with peregrine falcons and bald eagles than gray wolves; luckily there is not a lobby for hunting pelicans. According to Audubon California, there is still some reason for concern, especially from the effects of oil and sewage spills on coastal habitats.

From a broader perspective, this delisting comes at a time when many species are still at risk. This week reported that (so far) the Obama administration is listing endangered species at an even slower pace than the Bush administration. This may be partly due to delays in getting officials confirmed by the Senate, and perhaps also the administrative foot-dragging during the last administration played a role in backing up the queue. However, these candidate species need to be listed soon so that they, like the brown pelican, have a chance at recovery.

Wednesday, November 11, 2009

A Landscape Component for Green Buildings

A coalition of organizations has formed the Sustainable Sites Initiative, a project to reduce the environmental impact of developed sites. The project is run by the American Society of Landscape Architects, the Lady Bird Johnson Wildflower Center, and the U.S. Botanical Garden. The goal is to create a complement to existing LEED ratings for sustainable structures, and the guidelines may eventually be incorporated into LEED. Their standard could be applied to any developed site, with or without buildings.

You can read the guidelines (pdf) at their website. To me, they appear quite thorough in addressing the worst impacts that human development can have on a landscape. There are guidelines for site selection, water use and runoff, soil and vegetation management, construction materials and techniques, human health effects, and site operation. They encourage "smart growth" patterns – away from farmland or wild areas and into established communities and urban areas with existing transportation infrastructure.

The sustainable sites standard falls somewhat short on wildlife impacts. To their credit, the guidelines require that new construction not disturb any endangered or threatened animals or plants on a site and that habitats used by those species be preserved intact. They also recommend reducing light pollution and cite its impact on migratory birds. They require the control of invasive species and suggest the use of native, site-appropriate plants for landscaping. These are all important steps towards sustainability that ought to benefit wildlife.

However, in perusing the guidelines, I did not see any requirement or credit for reducing window strikes, one of the most serious impacts that human development has on birds. There is a trend in contemporary architecture, encouraged in part by LEED ratings, towards designing buildings with large expanses of glass. While these are often aesthetically pleasing, they prove deadly to birds that do not see the glass as an obstruction. However, there are ways to reduce these strikes, either by reducing the amount of glass or making glass easier for birds to see. A truly sustainable development standard ought to incorporate these methods.

Tuesday, November 10, 2009

EPA Finds That Greenhouse Gases Threaten Health

Yesterday the EPA took another step towards regulating greenhouse gases by sending its final endangerment finding to the White House.

Sources said the document concludes the emissions pose a threat to the public's health and welfare. The agency did not release its finding, which was issued as a draft in April. The Office of Management and Budget now has 90 days to sign off on it.

Environmentalists embraced the move as a sign that the Obama administration is moving ahead on global warming policy less than a month before U.N.-sponsored climate talks begin in Copenhagen....

Keith McCoy, vice president for energy and resources policy at the National Association of Manufacturers, said his members are worried that the Obama administration would put in place rules on greenhouse gases before Congress had a chance to pass climate legislation. While the House has passed a climate bill, the Senate is unlikely to take up its version of the measure before next year.
If the EPA has concluded that greenhouse gas emissions present a threat to human health, then it would be compelled under the Clean Air Act to issue regulations to control those emissions. The ability of the EPA to provide an alternate path towards climate change regulations puts some pressure on the Senate to pass a bill. Legislation gives representatives from energy-producing regions more influence in how those regulations will affect their states. Regulations issued under the Clean Air Act could be much more strict than cap-and-trade legislation.

For that reason, it does seem like an inviting alternative to whatever legislation, if any, that the Senate produces. But those regulations could be blocked by riders on appropriations bills, as has happened in the past.
Could the same thing happen to EPA regs that happened to CAFE regs under Clinton? Well, Sen. Lisa Murkowski (R-Alaska) has already tried once, back in September. Her amendment was poorly written and she ultimately backed down without forcing a vote on it. But as the aide told me, it would be possible for a more adept legislator to write a more carefully tailored amendment that would block only the stationary-source regulations and leave the (more popular) vehicle regulations untouched. Obviously Republicans don’t control Congress now, and unless the most catastrophic predictions play out, won’t in 2010 either. But hostility to EPA regulations on power plants cuts across party lines. And remember, what’s needed here isn’t 60 votes against the EPA regs per se—just 60 senators who think passing an appropriations bill is more important than standing up for the EPA. The thing about appropriations bills is that they really need to pass or parts of the federal government go unfunded. There’s enormous pressure; that’s why members of Congress are fond of attaching riders to them....

If there’s a sufficiently large bloc of senators motivated to block the EPA, they’ll probably find some way to block it. But the point here is not so much to try to predict what might happen. It’s just to say that EPA regulations of CO2 are not “inevitable.” Nothing in politics is inevitable; nothing’s a sure thing; everything’s a risk; everything’s a fight. Those who would abandon legislation in Congress in favor of EPA regs run at least some risk of consigning the U.S. to years without any restrictions on CO2 emissions.
So even with an endangerment finding, much remains uncertain about the future course of greenhouse gas regulations.

Albatrosses Threatened by Commercial Fishing

Many albatross species are in decline because of their interaction with commercial deep sea fishing. Albatrosses are attracted to the same bait used to catch fish. When they attempt to grab and eat bait, they often become entangled in the fishing lines and drown. As a result, 18 seabird species are threatened with extinction. Another 19 seabird species are at risk.

A conference this week will consider ways to reduce these accidental killings along with their main business of setting tuna quotas.

300,000 Starlings in a Single Flock

While in rural parts of New Jersey or the Delmarva Peninsula I have occasionally seen large starling flocks, numbering perhaps in the low thousands. I always find these flocks impressive, especially when they take off. But I have never seen a flock like this one.

[From LiveLeak via HuffPo]

Monday, November 09, 2009

Mute Swans at Cape May Meadows

Many mute swans are already displaying their characteristic arched wings.

Not all of them were looking quite so festive.