Wednesday, August 31, 2011

Arrowwood as a Food Plant

Among the shrubs frequently recommended for wildlife-friendly yards are the various species of Viburnum, especially Arrowwood (Viburnum dentatum). Arrowwood is a medium-sized shrub with toothed, egg-shaped leaves. The toothed appearance accounts for its species name, dentatum, while "arrowwood" refers to its use by Native Americans for arrow shafts. Arrowwood ranges across the eastern United States, from Maine south to Florida and west to Iowa and Texas. It occurs in a variety of habitats and soil conditions and adapts well to partial shade.

In spring, Arrowwood bears bunches of small, white flowers. These flower bunches are attractive to many insects. I often saw bees and flies hovering around and nectaring at the flowers so that there was a constant hum of insect wings around the shrub. On some occasions I saw carpet beetles, like the ones in the photo above, foraging on the flower bunches. I think these may be Varied Carpet Beetles (Anthrenus verbasci). The beetles, in turn, were preyed on by ants.

As the summer progressed, the shrub dropped its flowers and the clusters started forming berries instead. Meanwhile, the toothed leaves themselves became food. I never discovered what was eating the leaves. According to a USDA fact sheet (pdf), Arrowwood may be vulnerable to the introduced Viburnum Leaf Beetle (Pyrrhalta viburni), which skeletionizes the leaves. In addition, Viburnum is a larval host plant for many species of Lepidoptera, including the Hummingbird Clearwing (Hemaris thysbe), Io Moth (Automeris io), Imperial Moth (Eacles imperialis), Cecropia Moth (Hyalophora cecropia), Gray Dagger (Acronicta grisea), and Baltimore Checkerspot (Euphydryas phaeton), to name a few.

As the berries ripen, they turn from light green to dark blue. I suspect that the fruits are the main reason for their inclusion in lists of wildlife-friendly plants since such recommendations tend to be targeted to birders. Arrowwood is an excellent food source for birds, in addition to the insects I have mentioned above.

The berries disappear from their stems very quickly, as birds find and eat them. They seem especially appealing to Gray Catbirds and American Robins, though other birds may also take advantage of them. In my area, the berries ripen in mid-August, which is a little too early for the bulk of songbird migration but just about right for hatch-year birds gaining independence and all songbirds fattening for their southbound migrations.

Tuesday, August 30, 2011

Vagrant Birds from Hurricane Irene

Hurricane Irene Reaches New York City / Credit: NASA/NOAA GOES Project
Tropical cyclones like Hurricane Irene are well-known among birders for carrying numerous birds far from their normal ranges. Aerial waterbirds – those that earn their living on the wing over open ocean – are particularly prone to displacement. The prospect of seeing storm-blown birds, especially ones that one would normally need to travel or take a pelagic trip to see, lures birders to coastal areas or inland spots with open water even before a storm has completely subsided. I made some mostly unsuccessful attempts to find unusual birds at my usual spots. Other birders had much better luck, and it turns out that Irene's track was particularly conducive to sighting entrained birds from land in this area.

Here are a few of the sightings that have been reported so far:
Finally, the Hurricane Irene 2011 blog has been collecting sightings from throughout the areas affected by the storm. The Philadelphia Inquirer has an article on hurricane birding in the Philadelphia area. If you live in or near the storm's path, did you see any unusual birds this weekend?

Monday, August 29, 2011

Birding after the Storm

The worst parts of Hurricane Irene passed through New Jersey in the early morning hours. The eye made landfall in the state around 6 am near Little Egg Inlet, the waterway between Atlantic City and Long Beach Island, very close to the Brigantine portion of Forsythe NWR. It was only the third storm to make landfall in New Jersey as a hurricane and the first since the Vagabond Hurricane of 1903. It continued up the coast and degraded into a tropical storm as it reached New York City.

Donaldson Park was flooded by the surging Raritan
As the eye was passing Central New Jersey, I took a walk down to Donaldson Park, my local patch, to see if any unusual birds were around. As I expected, the park was completely flooded. There were about 150 Laughing Gulls, as well as flocks of swallows (mostly Tree Swallows), taking advantage of the newly flooded fields. As I mentioned in yesterday's post, that many Laughing Gulls is very unusual for the site. I looked for terns but saw none. Even something common like a Forster's Tern would have been a nice sighting for the location.

There was not too much damage in my neighborhood, just some limbs down and one fallen tree, as far as I could see. The carpenter bee above was apparently killed by the storm, either by drowning or by being slammed into the ground by a gust of wind. A baby squirrel must have been knocked out of its nest by the wind.

In the afternoon, I went out again, this time across the Albany Street Bridge into New Brunswick. The bridge is closed because of flooding on the New Brunswick end, and Route 18 is closed because of flooding in multiple places. The river is very high right now, and it is expected to get worse before it gets better. The Delaware and Raritan Canal, its towpath, and Boyd Park have disappeared under the flood waters.

As I walked across the bridge and along Route 18's deserted northbound lanes, I kept an eye out for interesting birds. There were a lot of swallows around; I identified both Barn Swallows and Tree Swallows, but not any others. About 100 Laughing Gulls were in the air. Beyond that, I did not see anything out of the ordinary.

Sunday, August 28, 2011

Riding out Irene

Yesterday morning, I walked through my local patch, Donaldson Park, in the hope of seeing some unusual birds before the storm arrived. Most of the birds I saw were the usual ones, highlighted by a flock of several dozen Brown-headed Cowbirds. One Spotted Sandpiper joined the usual Killdeer on the mudflats along the Raritan. I stood for a while and watched for bird activity at the east end of the park, which has an unobstructed view of the river down to the US 1 bridge. A few Double-crested Cormorants flew past, along with a few Laughing Gulls. The latter is a common coastal bird, but I rarely see it at that particular location. Maybe the easterly winds carried a few in from Raritan Bay.

Here are a couple photos from later in the day.

Saturday, August 27, 2011

A New Shearwater Species, Most Likely Extinct

Federal scientists have discovered and named a new bird species for the United States, Bryan's Shearwater.
For the first time in decades, researchers have found a new bird species in the United States. Based on a specimen collected in 1963 on Midway Atoll, Northwestern Hawaiian Islands, biologists have described a new species of seabird, Bryan’s shearwater (Puffinus bryani), according to differences in measurements and physical appearance compared to other species of shearwaters. Scientists at the Smithsonian Conservation Biology Institute analyzed the specimen’s DNA to confirm that it is an entirely new species....

The Bryan’s shearwater is the smallest shearwater known to exist. It is black and white with a black or blue-gray bill and blue legs. Biologists found the species in a burrow among a colony of petrels during the Pacific Ocean Biological Survey Program in 1963. Peter Pyle, an ornithologist at the Institute for Bird Populations, recently examined the specimen and found that it was too small to be a little shearwater (P. assimilis) and that it had a distinct appearance.

According to Fleischer and Andreanna Welch, a former graduate student and Smithsonian predoctoral fellow at SCBI who worked on the genetic analysis, the Bryan’s shearwater differs genetically to a greater degree than found between most other species of its genus, and is distantly related to another similar looking species, the Boyd’s shearwater (P. boydi). Based on this DNA evidence, researchers estimate that the Bryan’s shearwater separated from other species of shearwaters perhaps more than 2 million years ago. These findings have been published in a paper, "A New Species of Shearwater (Puffinus) Recorded from Midway Atoll, Northwestern Hawaiian Islands," in the current issue of The Condor.

Researchers do not know where Bryan’s shearwaters breed. According to Pyle, shearwaters and other seabirds often visit nesting burrows on remote islands only at night, and researchers have not discovered the breeding locations of many populations. Individual seabirds from colonies also often “prospect” for new breeding locations, usually far from existing colonies. Bryan’s shearwater could conceivably breed anywhere in the Pacific ocean basin or even farther afield.

“We don’t believe that Bryan’s shearwaters breed regularly on Midway or other Northwestern Hawaiian Islands, based on the extensive seabird work in these islands during the Pacific Seabird Project,” Pyle said. The specimen was the only observation during this extensive project, which occurred on islands and atolls throughout the North Pacific from 1963 until 1968. “They would have encountered more Bryan’s shearwaters if they bred regularly in the Northwestern Hawaiian Islands.”

Given that Bryan’s shearwaters have remained undiscovered until now, they could be very rare and possibly even extinct.
The abstract of the paper is available here.

It is sad to think that a newly discovered species might already be extinct, but that is not surprising for birds that have gone undiscovered for so long, especially ones that occur within the United States and its territories.

Friday, August 26, 2011

Loose Feathers #305

Whimbrel with a transmitter / Photo by Barry Truitt, The Nature Conservancy
Birds and birding news
Nature blogging
Environment and biodiversity

Thursday, August 25, 2011

Avian Ancestors

Over at LiveScience there is a new gallery of images of avian ancestors and dinosaurs with various bird-like traits. The images are mostly artists' conceptions, with a skeletal reconstruction or fossil photograph here or there. There are some that look clearly like birds, but there are a lot more with a classic bipedal dinosaur shape, but with feathers attached. As I looked over the galleries, I was thinking about how much the image of dinosaurs has changed from what I learned when I was growing up. Back then, dinosaurs were portrayed as blandly colored and scaly, more like giant monochrome lizards than anything remotely bird-like. A large part of that has to do with recent discoveries like Gansus yumenensis and Epidexipteryx hui. Some also is a result of re-conceiving how dinosaurs looked and acted. Either way, it is fascinating to think about how bird ancestors evolved and separated from dinosaurs.

One caveat about the gallery is that it does not seem to take account of the recent revision to Archaeopteryx's status as a bird ancestor.

Wednesday, August 24, 2011

Carpenter Bee on Phlox

Yesterday evening I found this carpenter bee sitting on the flower head of a phlox plant. It was sitting almost perfectly still, with its head tucked down near the bases of the flowers. This behavior is something I have observed with both carpenter bees and the slightly smaller bumble bees. The most likely explanation I have read is that they are biting the bases of the flowers to sip the nectar without pollinating the plant. This makes sense since I am not sure even a carpenter bee could get its tongue far enough down a phlox flower. The odd thing, though was that it remained so still, without the visible twitching of antennae or other body parts that I normally see on nectaring insects. It stayed still even as I kept bumping my camera into the plant to get better angles for photos.

As you may have heard, we had some excitement on the East Coast in the form of a 5.8 magnitude earthquake. There was a lot of chatter generated by it, probably disproportionate to the magnitude of the event. There were a few news items that might be of interest to some of you. First, contrary to initial reports, there was some building damage in Virginia and the DC area, including the collapse of finials on the National Cathedral's main tower. Second, PhysOrg explains why the earthquake was felt over such a large area, from Georgia north to Quebec and west to Wisconsin. Scientific American has a list of the top ten East Coast earthquakes. Finally, here is an interesting bird-related note from the National Zoo:
The first warnings of the earthquake may have occurred at the National Zoo, where officials said some animals seemed to feel it coming before people did. The red ruffed lemurs began “alarm calling” a full 15 minutes before the quake hit, zoo spokeswoman Pamela Baker-Masson said. In the Great Ape House, Iris, an orangutan, let out a guttural holler 10 seconds before keepers felt the quake. The flamingos huddled together in the water seconds before people felt the rumbling. The rheas got excited. And the hooded mergansers — a kind of duck — dashed for the safety of the water.

Tuesday, August 23, 2011

Spread of Eurasian Collared-Doves

A couple weeks ago I saw my life Eurasian Collared-Dove in Cape May Point. As it turns out, these doves are far more common in North America than I knew, at least outside of the Northeast. Their population in Oregon has grown rapidly:
Actually, the Eurasian collared dove has been cropping up in Oregon since 1998 or '99 and, according to local Audubon Society records, it first was spotted in Corvallis in 2007. But now the bird's mid-valley numbers really seem to be taking off.

"This is something new," said David Mellinger, vice president of the Audubon Society of Corvallis. "They reached Corvallis a couple of years ago, and suddenly they're all over the place. It seems to be good habitat for them." ...

Although Eurasian collared doves feed on grains and seeds, there have been no reports of crop damage so far, according to the Oregon Department of Agriculture. It's not yet clear whether the new arrivals pose any threat to native species such as mourning doves and band-tailed pigeons.

"The jury's still out on that one," said Rick Boatner, who tracks invasive species for the state Department of Fish and Wildlife. "But it does appear they're expanding their range in Oregon." ...

"It's kind of an interesting story," said Cornell's David Bonter, director of Project FeederWatch, which monitors bird numbers across North America....

By the early '80s, Eurasian collared doves were breeding in Florida, and they soon established themselves in the Southeast.

"Then, between 2000 and 2007, they made this remarkable expansion from Florida all the way to the Pacific Northwest. Now they're found from Florida all the way to Alaska," Bonter said....

Like a couple of earlier European invaders, the starling and the house sparrow, the Eurasian collared dove is highly adaptable and does well in urban environments, two factors that help to explain its rapid advance across the United States, Bonter added.

"They're a bird that really does well in human-modified landscapes, and we've done a good job of making the world friendly to Eurasian collared doves," he said. "There's no doubt in my mind that the Eurasian collared dove will continue to expand and will become one of the most common birds at backyard bird feeders."
In that case, we might be seeing quite a lot of these in New Jersey fairly soon.

Monday, August 22, 2011

Now with a Mobile Version!

One of the changes that has been on my wishlist for Blogger for a while has been a mobile template. While I like my current blog template, it was not designed with mobile devices in mind. On some devices, it can display very poorly or be nearly unusable. So I was happy to discover that Blogger has started supporting mobile templates.

I must have missed the announcement because I only discovered this option recently when I was looking for something else on my blog's settings pages. I set it up as soon as I saw the option was available. A screenshot from a friend's iPhone is at right. Now if you access my blog from an iPhone, Android, or other mobile device, Blogger should detect it and render the mobile template automatically.

If you want this for your own blog, you need to enable the option yourself and pick a template. In Blogger in Draft (the default dashboard I have been using), the mobile option is under Dashboard > Template. In standard Blogger, the option is under Dashboard > Settings > Email & Mobile. If you want to read more about it, see the announcement.

Sunday, August 21, 2011

Birding the Middlesex Coast

Elsewhere in the Garden State, birders were delighting in a rare sighting of a Brown Booby in Jarvis Sound near Cape May. The booby was seen by the naturalists aboard The Osprey, a pontoon boat that runs daily birding excursions during the warmer months. I have taken several trips on that boat, and none of them turned up any birds that exciting!

Great Egret in a tree
I only found out about that rarity after returning home from an excursion to the Middlesex County portion of Raritan Bay. The first stop was at South Amboy's Morgan Avenue mudflats. As usual, there was a squad of Great Egrets perched in a small grove of trees close to the beach. The egrets were joined by one immature Yellow-crowned Night Heron. When I turned to keep walking along the beach, I saw two dark, spindly birds in flight over the marsh. I found them with my binoculars, and they turned out to be two Glossy Ibises. They circled a few times before finally settling somewhere in the marsh.

Yellow-crowned Night Heron
As I continued out towards the spit, I could see a man with a metal detector walking around out on the beach. He walked out along the spit to cross the creek, close enough to the hundred or so birds gathered there to flush all of them. By the time I got out to the spit, there were few birds around, and most of those were in flight. I started looking at the many Osprey, and I was looking at one, two light-colored birds passed through my field of view. When I got on them, I saw that they were two Caspian Terns – heavy-billed for terns, with a dark cap extending from their bills to the backs of their heads (unlike Royal Tern at this time of year).

Semipalmated Sandpiper
The second stop was at Pirate's Cove. Here again, the birds on the sandbar got flushed. Despite that, there were some Semipalmated Sandpipers and Semipalmated Plovers along the shoreline, and it was possible to get fairly close without flushed them. One Ruddy Turnstone flew back and forth a few times, and Common and Least Terns were both present.

Semipalmated Sandpipers
A third stop at Cliffwood Beach Park, just over the creek from Pirate's Cove, turned up the same set of birds as at Pirate's Cove. There is a short section of boardwalk that might provide a good viewing point for someone with a spotting scope. The beach running west from Whale Creek was mostly unproductive, though there was a nice collection of terns near the Laurence Harbor end.

Saturday, August 20, 2011

Range Shifts Linked to Climate Change

Red-banded Hairstreaks are expanding northward.
Many studies over the past decade have tried to document how animals adapt their ranges in response to a warmer climate. A recent paper analyzed data from over 50 such studies to get a sense of the bigger picture.
The findings indicate that among the plants and animals tracked in the studies, species over all were escaping to higher elevations at an average rate of 36.1 feet per decade and moving away from the equator at a rate of 10.1 miles per decade. That’s a steady march poleward of eight inches per hour. Those two rates are respectively two and three greater than those found in the last similar meta-analysis in 2003.

The data also clearly indicates that the species changing their distribution the most rapidly are those in regions where the most warming has occurred.

While the study pulled together literature from around the world, the vast majority of available research comes from Europe and North America, leaving big holes in global understanding how species in one of the most biologically rich areas, the tropics, are responding to climate change.

These unanswered questions are further complicated by the primary role of precipitation, as opposed to temperature, in distributing most species in the tropics. The precise effects of climate change on precipitation are still a source of debate and uncertainty.

Friday, August 19, 2011

Loose Feathers #304

Roseate Tern / Photo by Amanda Boyd (USFWS)
Birds and birding news
  • A new study examines rediscoveries of long-lost species, such as Hawaii's Greater Akialoa, which went a long time without sightings, was rediscovered in the mid-20th century, and is now considered extinct with no sightings since 1969. The paper argues that conservation measures are necessary to make sure vulnerable rediscovered species are not promptly lost again.
  • The reintroduction of red wolves into North Carolina is changing the local ecosystems. The wolves prey on raccoons, which helps ground-nesting birds such as Bobwhite and Wild Turkey since raccoons often rob their nests. Red wolves also hunt white-tailed deer, but so far their pressure on the deer population has been insufficient to change the soil or plant life significantly.
  • The Emperor Penguin that languished on a New Zealand beach has recovered and is being returned to its normal range. It was fitted with a tracking device and will be released at sea.
  • The Piping Plover colony at Revere Beach in Massachusetts has had outstanding productivity over the past several breed seasons. A single pair fledged four chicks in 2009, and three pairs fledged 11 or 12 chicks in 2010 (3.66 per nest). This year's numbers are likely to be similar.
  • The autumn hawk watch at Hawk Mountain began on August 15. Cape May has not started its hawk watch yet, but the "Morning Flight" watch began on August 16. You can follow the progress of that and other migration watches on CMBO's View from the Field blog.
  • The British Trust for Ornithology used satellite trackers to follow the migration journeys of five Common Cuckoos from England to Africa. Follow the link to see a map of their routes.
  • Little Penguins could disappear from Australia's Granite Island. Over the past ten years, the colony's population has fallen from 1,600 to 146.
  • A podcast from Scientific American discusses the importance of reconnecting forest fragments to restore bird diversity after an area has been deforested. The study in question examined rainforest fragments in Brazil, but it is probably applicable elsewhere as well.
  • A study of Rock Ptarmigans found that large males that can run the fastest tend to be most successful at breeding.
  • Here is a photo of an Andean Cock-of-the-Rock.
  • The Press of Atlantic City profiles the "Birdman of Margate" who feeds sparrows on the sidewalk in front of his house every day.
Nature blogging
Environment and biodiversity
  • A project in Belo Horizonte (Brazil) is highlighting the loss of urban street trees by drawing chalk outlines on the street where trees were cut down. The city is cutting down trees almost twice as fast as it is replacing them, so that many streets are left without the benefits of shade. (via bioephemera)
  • There is a bad situation in the North Sea as an offshore oil pipeline has started leaking, initially spilled over 50,000 gallons, and could continue to develop additional leaks
  • The wall along the U.S.-Mexico border is obstructing normal wildlife movements, leading to fragmentation of vulnerable populations, particularly the Arroyo toad (Anaxyrus californicus), the California red-legged frog (Rana draytonii), the black-spotted newt (Notophthalmus meridionalis), the Pacific pond turtle (Clemmys marmorata), and the jaguarundi (Puma yagouaroundi). This is not an unforeseen consequence, as many environmentalists warned that this would be a problem before the wall was constructed. It remains to be seen if any mitigation measures can prevent long-term damage.
  • Via Bug Girl, some Staten Island residents do not appreciate the Cicada Killer wasps that help keep the cicada population in check. The main objection seems to be that the dig nesting holes in people's lawns.
  • All but two of the 104 endangered Mountain Yellow-legged Frogs rescued from the San Jacinto fire in 2009 have died in captivity
  • A primitive eel found off the island of Palau has anatomical features unlike any other eel and likely evolved 200 million years ago. This eel is so different from other eels that classifying it required creating a new family (Protoanguillidae) as well as genus and species (Protoanguilla palau).

Thursday, August 18, 2011

ESA Protection for Foreign Bird Species

Slender-billed Curlew
Last week the US Fish and Wildlife Service added several birds that occur mainly outside the United States to the Endangered Species List. Such listings mainly serve to enforce trade restrictions, though they may have other benefits such as funding or coordination of conservation activities for their recovery.

The first decision involved four parrot species:
The Service finds that listing the Philippine and yellow-crested cockatoo as endangered, and listing the white cockatoo as threatened, is warranted and is issuing proposed rules to list these species. In addition, the Service is proposing a special rule for the white cockatoo. If adopted, the proposed special rule would allow import, export and interstate commerce of certain white cockatoos without a permit under the ESA, provided the provisions of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Wild Bird Conservation Act (WBCA) are met. The Service finds that listing is not warranted for the crimson shining parrot. The not warranted status for the crimson shining parrot is a final agency action.
The second batch included six other species:
The rule implements federal protections provided by the ESA for the Cantabrian capercaillie, Marquesan imperial pigeon, Eiao Marquesas reed-warbler, greater adjutant, Jerdon’s courser, and slender-billed curlew. Populations of each of these species are small, fragmented, and declining, making them particularly vulnerable to genetic threats associated with small populations and extinction....

Significant threats to these six foreign bird species include habitat loss, overutilization and inadequate existing regulatory mechanisms. Information on climate change was available for only one species, the slender-billed curlew; based on this information the Service found climate change to be a potential threat to this species.

Miami Blue / NPS
The listing activity included emergency listings for several butterflies with restricted ranges, including the endemic Miami Blue. An emergency listing protects a species for 240 days, during which time the agency has time to draft and publish a final listing.
The Miami blue is a small, coastal, non-migratory butterfly endemic to south Florida. Its geographic range once extended from the Dry Tortugas north along the Florida coasts to about St. Petersburg and Daytona, but it is now restricted to a few, small, remote islands within the Florida Keys. In making this emergency listing determination, the Service has carefully assessed the best scientific and commercial information available regarding the past, present, and future threats faced by the Miami blue butterfly....

The Miami blue butterfly is endangered due to the combined influences of habitat destruction and modification, herbivory of host plants by exotic green iguanas, accidental harm from humans, loss of genetic diversity, and catastrophic environmental events, such as hurricanes. Because of its small population size and restricted range, collection can severely impact the Miami blue.

Imminent threats now pose significant risk to the survival of the Miami blue. The Service believes emergency listing is necessary and, in this case, the normal listing timeframe is insufficient to prevent losses that may result in extinction. In addition, the Service has determined that designation of critical habitat for the Miami blue butterfly is not prudent because publishing maps and descriptions of critical habitat areas would widely announce the exact location of the butterfly to poachers, collectors, and vandals and may further facilitate disturbance and destruction of the butterfly’s habitat.
Emergency listings will also protect the Cassius Blue, Ceraunus Blue, and Nickerbean Blue butterflies, despite their wide ranges due to their similar appearance to the Miami Blue.

Wednesday, August 17, 2011

Comments Needed for Cape Hatteras Management Plan

Via The Drinking Bird, I read that the National Park Service is seeking comments on its management plan for off-road vehicle (ORV) use in Cape Hatteras National Seashore. The plan is the result of a long, contentious process and seeks to balance recreational ORV use on Cape Hatteras with the needs of wildlife, particularly beach-nesting Piping Plovers. An interim plan restricting ORV use has been in place for several years, and during that time populations of beach-nesting shorebirds have rebounded (pdf) after a decade of decline.

Since there is vocal and persistent opposition to any restrictions on ORV use, it is important that birders and other recreational visitors to the seashore make their voices heard during the public comment period.. Comments do not need to be long; a short comment should be enough to let federal officials know that there is public support for wildlife protection. Nate suggests including two points:

1) I support a regulation to manage ORV use within the Cape Hatteras National Seashore.

2) The regulation should include science-based protections for wildlife and vehicle-free areas for wildlife and pedestrians.
Submit comments here by September 6.

Tuesday, August 16, 2011

Wet Flowers

Over Sunday and Monday, New Jersey received a tremendous amount of rainfall, enough to set records in some places. It provided a good opportunity for some raindrop photography, in this case a waterlogged Rose of Sharon shrub.

Monday, August 15, 2011

Eurasian Collared-Dove at Cape May Point

While I was down at the shore last week, I managed to see a Eurasian Collared-Dove that has been hanging around in Cape May Point for the last several weeks. Apparently there is also a second bird, which I did not see. This was a life bird for me, and it brought my life list up to 350 species. It was larger than I expected, built more like a Rock Pigeon than a Mourning Dove.

Eurasian Collared-Doves originated in southern Asia and gradually spread west and north into Europe. In the 1970s, some were released on Bermuda, and their population quickly grew and spread into North America from there. Their current range covers the Deep South, with pockets of breeding birds in the southern Great Plains and southern California. It would not surprise me to see their population spread further north, especially as the climate warms and becomes more hospitable to them. Their rapid spread has led to concerns about their invasive potential, though what effect they may have on native species like the Mourning Dove remains unknown.

Sunday, August 14, 2011

Common Tern

Like Laughing Gulls, terns are a notable feature of summers along New Jersey's waterways. Two species in particular predominate. One, the Forster's Tern, is often seen along the coast but seems to prefer inland waterways and marshes. The second, Common Tern, adheres more strictly to coastal beaches.

Terns are noted for their foraging behavior, in which they repeatedly hover and then plunge headfirst into the water for fish. Their pointed bills and forked tails give them a sleeker appearance than gulls, their closest relatives in the avian evolutionary tree.

Always remember to watch your back during preening.

Saturday, August 13, 2011

Laughing Gulls

Gulls in the eastern United States are at their peak diversity in winter when the local breeders are joined by birds from further north, including a few species that breed in or near the Arctic. There is one characteristic gull of summer, though, the Laughing Gull. From May through August, Laughing Gulls are often the most numerous gull species on the shore, particularly along New Jersey's southern coastline, which houses one of the largest breeding colonies of Laughing Gulls on the continent. At the peak of breeding season, their ha-ha-ha-haaaaaaaaaaa-haaaaaaaaaaaaa calls can be deafening.

In spring and early summer, these are among the most attractive gulls, with sleek black hoods, crisp white semicircles around their eyes, and striking red bills. By late summer, the adults have already started to shed their hoods as they molt into their winter (basic) plumage. Their mantles are a mix of fresh and worn feathers, and their bright red bare parts are now muted.

In late summer, Laughing Gull flocks also feature recently-fledged immature birds, given away by the brownish coloration of their mantles and their grayish bodies.

Like other gull species, Laughing Gulls are opportunists. They are not above snatching food from barbecues and beachgoers or robbing the local tern colonies. They also forage for themselves, as I saw this gull doing. It was picking items up out of the surf and eating them. Most of their diet consists of invertebrates, such as insects, crustaceans, and mollusks.

Friday, August 12, 2011

Loose Feathers #303

Roseate Tern / Photo by Kirk Rogers (USFWS)
Birds and birding news
  • Swarms of black flies may be hampering the efforts to establish a second migratory flock of breeding Whooping Cranes. The flies may discourage the cranes from mating, staying on their nests, and rearing their young. 
  • The breeding population of Black Skimmers in Texas has declined, most likely due to human disturbance.
  • Wind turbines pose a significant threat to birds and bats, especially the latter since bats can be killed by air pressure changes without striking the turbine. The U.S. Fish and Wildlife Service is working on guidelines to reduce the impacts of wind development. The best solution may be to place wind farms away from known migration corridors.
  • This summer, California Common Murre chicks hatched on the Channel Islands for the first time since 1912.
  • Nazca Boobies that are abused as chicks tend to bully other chicks once they reach adulthood themselves.
  • Computer models suggest that the changing shapes of pigeon and starling flocks are due to birds in the flock turning individually and maintaining a constant speed, among other factors. 
  • The Conserve Wildlife Foundation of New Jersey is creating online range maps for the state's species of special concern.
Nature blogging
Environment and biodiversity
  • Continued oil sands development is likely to negate any gains Canada makes in reducing its greenhouse gas emissions elsewhere.
  • The Obama administration has started approving leases for Arctic offshore drilling even though the Coast Guard lacks the infrastructure to respond to a spill. Royal Dutch Shell gained drilling rights to a site in the Beaufort Sea 20 miles offshore from the Arctic National Wildlife Refuge. 
  • Conservationists in Texas worry that this year's drought will do long-term damage to the state's wildlife habitat.
  • High atmospheric oxygen levels may explain why insects (especially dragonflies) of the Carboniferous Period grew so large. Larvae may have been forced to grow large to avoid oxygen poisoning.

Thursday, August 11, 2011

Book Note: The Atlas of Birds: Diversity, Behavior, and Conservation

With nearly 10,000 species, birds are easily the most diverse class of vertebrate animals. In addition to being diverse, birds are also highly visible, with all but a relative few species groups being active during the day. These traits make birds an attractive subject for scientific research and citizen science projects, so that there is a lot of published data about them. Mike Unwin presents a wealth of this data in graphical form in The Atlas of Birds: Diversity, Behavior, and Conservation.

While the book is called an atlas, it is not just maps. It also has numerous  photographic illustrations and statistics presented as pie charts or in some other graphic. One chapter how birds evolved and what makes them unique as a class. A second deals with relative bird diversity and protected areas across each continent. It is striking just how much more diverse the southern hemisphere, especially South America, is compared to the northern hemisphere. Then Unwin charts bird distribution by order. Very few orders are present on only one continent, but some are highly regional. A fourth chapter deals with bird behavior. The maps in this section serve mainly to show where example species live, though a few show migration routes. Most of the graphics in that chapter depict things like foraging techniques and field of vision. The fifth chapter covers the interaction between birds and humans – as meals, in culture, and as scientific subjects. The final two chapters cover conservation issues, both the many threats birds face and what is being done to protect them.

The Atlas of Birds: Diversity, Behavior, and Conservation is an attractive and useful reference that can provide birders a succinct view of how birds are faring around the globe.

Wednesday, August 10, 2011

Ambush Bugs

The goldenrod (Solidago sp.) and boneset (Eupatorium sp.) flowers at Scherman Hoffman were pretty to look at but were full of lurking predators. Some of them were various types of spiders, but the most numerous seemed to be these green and brown bugs. These unusual-looking insects are ambush bugs (subfamily Phymatinae, probably genus Phymata).

Ambush bugs sit still on flowers and stems and wait. When an unsuspecting insect approaches to sip a flower's nectar, it grabs the insect with its hooked forelegs and eats it.

Tuesday, August 09, 2011

Odonates at Scherman Hoffman

As I mentioned in Sunday's post, I visited Scherman Hoffman Wildlife Sanctuary last Saturday. Since morning was mostly overcast, there was a lot less insect activity than I anticipated. However, there were still a few nice dragonflies and damselflies active during the short breaks when the sun came out. Most of these were photographed around the small pond in the preserve's lower meadow.

This beautiful Eastern Pondhawk was resting on a rock.

So was this Common Whitetail.

There were a few damselflies perched on the grass stems in the pond. This one appears to be an Azure Bluet.

This large damselfly appears to be a Slender Spreadwing.

A Halloween Pennant was perched on a stem further out in the meadow.

Monday, August 08, 2011

Book Note: Avian Architecture

Since I reviewed Bernd Heinrich's The Nesting Season on Sunday, I would like to follow up by mentioning one other book on birds' nesting behavior that was published this spring. Peter Goodfellow's Avian Architecture: How Birds Design, Engineer & Build describes the diverse types of nesting structures that birds use around the world. Like several other books in Princeton's catalogue, Avian Architecture is the American edition of a book that originated with a European publisher, in this case Ivy Press in the United Kingdom.

The book breaks down the variety of birds' nesting structures into twelve nest types. Not all of them are strictly nests since one chapter is devoted to bowerbirds. These structure types are: scrapes, cavities, platform nests,  aquatic nests, cup nests, domed nests, mud nests, hanging and woven nests, mounds, colonial nesting, bowers, and edible nests. Each chapter deals with one nest type. It gives blueprints of typical nests within that type and then provides "case studies" with specific examples of how the nest type is implemented by the various bird groups that use it. Scrape nests, for example, are very simple to construct and tend to be used members of a few bird orders, especially Charadriiformes. Meanwhile, cavity nests are used by members of over 50% of bird orders – birds as diverse as chickadees, woodpeckers, hornbills, and Burrowing Owls.

Avian Architecture is well-illustrated with numerous photographs and diagrams. The blueprints are simple and give typical dimensions for a nest's width and depth. The case studies have photographs of actual bird nests. In some cases, the photographs are accompanied by paintings or drawings showing steps in nest construction or illustrating other aspects of nesting behavior.

Clearly, the best way to learn about nest building techniques is by watching birds construct their nests in person. Unfortunately not all of us have the leisure or travel budgets to see as many birds on their breeding territories as we might like. Given those constraints, books like Avian Architecture can help fill the gaps in our knowledge about birds' nesting behavior.

Sunday, August 07, 2011

A Visit to Scherman Hoffman

By the time I arrived at Scherman Hoffman yesterday morning, a sunny morning had turned into an overcast one. To some extent, this was a relief since Central Jersey residents were treated to a very hot July, and yesterday's overcast sky helped moderate the temperature. However, this moderation came at the cost of suppressing insect activity particularly that of the large insects (odonates and butterflies) that I had hoped to see.

The birds appeared to be mostly the same species that had bred around the refuge this summer. I had nice looks at several Gray Catbirds, a Downy Woodpecker, and a Blue-gray Gnatcatcher. Other birds that made their presence known through contact calls included Eastern Towhee, Eastern Wood-Pewee, Yellow-billed Cuckoo, Eastern Bluebird, White-breasted Nuthatch, and Tufted Titmouse. A Scarlet Tanager was present on one of the trails. The one definite migrant was a Solitary Sandpiper that I accidentally flushed from the pond in the lower meadow.

Several species of butterflies were active despite the clouds. The highlight was an Appalachian Brown, shown above. I have seen these fairly regularly over the past two months, so perhaps they are not as uncommon as I thought. Or perhaps they are just having a good year. Either way, I always enjoy seeing them.

Other butterflies included Spicebush Swallowtail, Question Mark (shown above), Common Buckeye, and Least Skipper.

There are still plenty of flowers blooming in the meadows around the refuge. One trail features a nice bushy crop of butter-and-eggs.