Bird Brains and Migration
A new study by Spanish scientists has found that non-migratory birds tend to have larger brains than migratory birds. Resident birds are more likely to find alternate sources of food and to try foraging techniques. Some European blackbirds have been observed using sticks to clear snow away from potential food sources. This provides an important advantage for resident birds during the colder months when food is scarce. Migration is an extremely stressful and hazardous journey so species that can adapt to the cold are better off staying put. There does seem to be some question about the cause and effect of the relationship between brain size and migration. Some seem to think that migratory birds are forced to migrate because they are not smart enough to adapt, while others argue that the small brain size is necessary to reduce the energy needed for the long migratory flight.
Thursday, June 30, 2005
Bird Brains and Migration
Tuesday, June 28, 2005
Birds and White-tailed Deer
The latest issue of Audubon magazine has an article on the problems caused by the white-tailed deer population boom. The problem has been apparent for years now; people who drive on rural roads (or even suburban roads in some places) are in constant risk of collision with a deer running across the road. The population is so large that deer are penetrating cities as well. There is a substantial herd in Rock Creek Park, including at least one gimpy individual. The deer in this herd have become relatively unafraid of humans.
The damage caused by large deer herds is not just a matter of traffic safety. As herds expand they begin to destroy the understory that other organisms need. This has a particularly heavy impact on birds:
In Warren, Pennsylvania, a 10-year study by the U.S. Forest Service determined that at more than 20 deer per square mile, there is complete loss of cerulean warblers (on the Audubon WatchList as a species of global concern), yellow-billed cuckoos, indigo buntings, eastern wood pewees, and least flycatchers. At 64 deer per square mile, eastern phoebes and even robins disappear. In heavily settled parts of Pennsylvania, where hunting pressure is light or nonexistent, it's not unusual to have more than 75 deer per square mile.This situation is pretty grim. Many bird populations are in serious trouble even without extra pressure from the deer population. Forests and parks that have been heavily impacted by deer browsing are easily discernible once you know what to look for. In such places you can see long distance and the understory consists mainly of barberry bushes and other invasive species that can resist deer.
Hunting is still the most effective way to control the population. Contraception has apparently proved impractical and relocating deer simply moves the problem around without a real solution. But hunting is fraught with problems. First there is the safety issue. Deer overpopulation is most heavily felt in areas where deer and humans come into close contact, and these areas are frequently off-limits to hunting because of the human population density. There is too much likelihood of human casaulties.Then there is the political opposition to using hunting as a way to control the deer population. The groups that are most visible in the opposition tend to be animal rights activists. But it is not the animal rights activists that have real clout on these issues. Oddly enough, the real political heavyweights are the hunters, especially in states where the fish and wildlife funding comes primarily from hunters. The experience in Pennsylvania is instructive: the program of increased hunting - and especially hunting does - was effective enough to make deer more afraid of humans, and thus harder to hunt, and the hunting lobby howled that there were no longer enough deer. Whether this really reflected a population decrease is questionable:
Data of a less anecdotal nature were collected last fall by the U.S. Army Corps of Engineers at its 22,000-acre property around Raystown Lake, in south-central Pennsylvania. Hunters were complaining bitterly that the deer had been shot out, but an infrared aerial survey revealed that the deer were merely doing what they do when they're hunted—evading hunters. One area contained 80 deer per square mile, and the average was 51—roughly three times what Alt and his management team had determined to be environmentally acceptable.The author (and presumably the Audubon Society) proposes changing the funding structure in states like Pennsylvania to decrease the fiscal influence of the hunting lobby. Funds could come from a dedicated tax, as was done in Missouri and Arkansas, or from private donations. Whether this will happen is another story:
The hunters and the commission reject all outside funding proposals because they want to keep the power where it is. Mohr, for example, is quoted by the York Daily Record as saying: “The problem with listening to all the special-interest groups is that, once you compromise, they've already gotten into your fort. Once nonhunters are telling you what you're going to accept, our days are over.”This strikes me as one obstacle to finding common cause between environmentalists and hunters - a strategy currently being hyped by some on the left. The Sierra Club and Kos have both presented such an alliance as critical to the future of the environmental movement. To a certain extent I agree with this position. There are areas where both can find common cause, especially when it comes to habitat preservation. But it seems to me that such an alliance will represent an uneasy truce more than a close partnership for the foreseeable future.
Monday, June 27, 2005
This evening there was an osprey hunting over the reflecting pool in front of the U.S. Capitol. I have seen one there before so I imagine it was finding something, but I do not know what fish would survive in that pool. Perhaps people abandon goldfish there.
I am adding an email address to the sidebar, but I am not going to give a mailto link to prevent automated spam crawlers from getting at it. Let's see if this works.
I have been adding links to the sidebar as well, and there are a few more that will probably go up within the next few days.
Sunday, June 26, 2005
As I mentioned in a previous post, I am still learning the ins and outs of birding by ear. I have most of the basics down, and I am building a good aural library of the easier calls. But some calls still leave me stymied. One of the hardest groups for me to nail down is the group of trill songs. There are differences, to be sure, but these differences sound much less certain out in the field than they do on the CD. So when I hear one of these trill calls coming from a tree, I am left scratching my head and trying to figure out whether the call is "dry" or "musical." And of course, the bird making the call is nowhere to be found, despite much searching with binoculars. On a hot summer day in D.C., two trilling species can safely be eliminated - dark-eyed junco and swamp sparrow. Chipping sparrow tends to be the most common breeding species of the remaining possibilities, but pine warbler and worm-eating warbler cannot be dismissed out of hand, as they have bred here in the past. (In fact, there is a probable breeding worm-eating warbler in SE DC this summer.) In most of these situations, I try to find the bird for a while, and then move on, frustrated. This happened to me several times today. I could only confirm the chipping sparrow as the source of a song in the Asian Garden; I did not discover the sources of the calls I heard elsewhere in the arboretum.
Birding Report: National Arboretum
The National Arboretum has remained as one of my favorite places to bird because of its nearness to me (only a 10-15 minute bus trip) and because a trip there combines a variety of birds with a good long walk. It is large enough (446 acres) that it is difficult to cover it all in one trip. (I usually only cover about 1/3 - 1/2 of the walking trails.) In some spots I find it easy to forget that I am in the middle of a city, even though U.S. Route 50 and the busy Northeast Corridor rail line pass right along one side of the Arboretum. The living exhibits and plant collections are managed in such a way to be a cross between showpieces and natural habitats. For example, the carefully tended Azalea Garden is situated on a wooded slope that has otherwise been allowed to go wild.
Recently the Arboretum began expanding its "no-mow" areas during breeding season. When I first started birding at the Arboretum two years ago, the only real "no-mow" areas were the fields around the Capitol Columns and the meadow area between the columns and Fern Valley. This summer, most of the fields that used to be mown during the summer have been allowed to grow, so that in most areas of the Arboretum there are meadows with grasses 2-3 feet tall. (These tall grasses are livened with butterfly weed and oxeye sunflowers, both of which could be found abundantly in any of the "no mow" areas.)
The program appears to be bearing fruit because field and edge loving species such as the indigo bunting could be found throughout the Arboretum. The real prize, though, was a yellow-breasted chat, a life bird for me. What a beautiful bird! It seemed a more intense yellow than its warbler cousins, and even the goldfinches with which it shared the meadow. There may have been a second chat, but I could not confirm it. The chat ducked in and out of the foliage, and it occasionally emerged on the top of a bush to sing its strange song. I cannot compare the gurgling and chattering song to any other bird vocalization that I have heard, except perhaps the gray catbird. While not an unusual bird in Maryland, it has been rare to find a chat in the District of Columbia, especially during breeding season. Yet this season there have already been several found: this one in the Arboretum, and more in several other locations where meadows have been allowed to form. We can hope that this will encourage more efforts to restore habitat where this is feasible.
Blue-gray gnatcatchers and Carolina wrens were plentiful throughout the Arboretum today. That is not particularly surprising. What is surprising was how many northern parulas I encountered. I had seen and heard parulas there last year, but only in the Azalea Garden. Today I heard them there, in Fern Valley, on the trail along the Anacostia River, and in the pine woods on Hickey Hill. I am glad there are so many of this lovely bird staying for the summer. Finally, I caught a glimpse of a white-eyed vireo foraging in the Asian Garden.
SPECIES SEEN AND HEARD - 39
Green Heron (overflight)
Yellow-billed Cuckoo (Azalea Garden)
Ruby-throated Hummingbird (Azalea Garden)
Eastern Wood-Pewee (Azalea Garden)
Acadian Flycatcher (Azalea Garden, Fern Valley)
Eastern Kingbird (meadow near Azalea Garden)
Northern Rough-winged Swallow (meadow near Hickey Hill)
Brown Thrasher (Azalea Garden)
Blue-gray Gnatcatcher (all over)
White-eyed Vireo (Asian Garden)
Red-eyed Vireo (Azalea Garden)
Northern Parula (all over)
Common Yellowthroat (meadow near columns)
Yellow-breasted Chat (meadow near Fern Valley)
Chipping Sparrow (riverbank, Asian Garden)
Indigo Bunting (all over)
Some Bird News from around the Web
County tests propane cannon to scare off airport birds
An airport in Alabama is using a 125 decibel cannon to scare off large birds on the runway. These birds are there because the airport recently revitalized wetlands right next to the runway. Perhaps revitalizing a swamp next to the airport wasn't the best idea, after all? My question is what effect will this have on the wetlands. Surely the herons and geese on the runways will not be the only creatures affected by this.
Birds in a death dive (Australia)
Presents a good reason not to allow reckless use of ATVs in national parks and other wild areas. Plovers nesting on Australian beaches are routinely disturbed by people riding their ATVs along beaches and through fragile dune areas. Nests are crushed and adults must neglect even the surviving nests for self-preservation. Unleashed dogs and rampant development are other common hazards. It appears that in Australia, as well as here in the U.S., beach-nesting birds are among those under the most pressure from humans.
Yellowstone River Bird Research
With summer well underway, it is also time for annual breeding bird surveys. Here in the Maryland and Washington area, the Maryland Ornithological Society is in the fourth year of a five year data collection program in preparation for the second edition of its breeding bird atlas. The first edition was based on data compiled in the mid 1980s.
The linked article reports on an ecologist studying bird populations along the Yellowstone River in Montana as part of a long-term plan for how best to meet human and environmental needs along the river. The population study covers 400 miles of the river and will be repeated over five years. With all the bad news regarding the environment these days, it is heartening to see these types of studies being integrated into a local planning process.
I found it interesting that she makes most of her identifications by ear. This is a skill that I have been trying to learn with moderate success, but I still have quite a ways to go!
Concerns arise over Bush's pick for EPA job
Apparently Bush's new appointee to head the enforcement division at the EPA - Granta Nakayama - has ties to industries under investigation. This really should come as no surprise after the recent resignation of an official (Philip Cooney) who repeatedly edited references to global warming out of administration documents. In this case, Nakayama is a partner in a law firm representing a company whose executives could face jail time if convicted of knowingly spreading asbestos-related diseases and concealing evidence of the danger from the public. Can Bush finally give us some environmental officials without such blatant conflicts of interest? Thanks to Plutonium Page at Daily Kos for the link.
Posted by John Beetham at 6/26/2005
Saturday, June 25, 2005
In the process of getting my new blog listed in as many directories as possible, I came across BlogShares, a website that tracks blog values much like the stock market. As far as I can tell, the "values" are based on incoming and outgoing links, as well as people "buying" and "selling" "shares." Apparently this is a growing blog with underpriced stock.
Perhaps I have gone a bit overboard with the listings.
Posted by John Beetham at 6/25/2005
Friday, June 24, 2005
Canada Goose Population Control
The ever-increasing numbers of
Large flocks of geese certainly have undesirable effects upon parks and local ecosystems. Excrement left on lawns and playing fields gets the most attention, but the geese can also wreak havoc on worthy goals like marsh or meadow restoration. The question, then, is what to do about it.
Contraceptives (or oiling of eggs) is probably preferable to the more "explosive" options. Dogs may disturb other nesting birds, and pyrotechnics affect all animals, not just the geese. Officials in
The active ingredient Nicarbazin does not build up in the bodily tissue of birds, dropping to undetectable levels five days after consumption, according to the Food and Drug Administration's Web site.
geese breed earlier than most other birds, other species who eat treated bait should not be affected, developers say.... Canada
A previous avian birth-control compound, Ornitrol, was pulled from the market in 1994 because it had adverse effects on non-target species, Wolf said.
The failure of the previous contraceptive should be cause for worry. Other birds will eat the bait provided. The newly-separated cackling goose seems particularly vulnerable to harm from this contraceptive program. The EPA ought to take the effects upon the various subspecies of
Whatever the merits of the contraceptive program, as well as more disruptive programs, in the final analysis the surge in goose population is the problem brought on by human manipulation. Parks, lawns, and artifical ponds provide geese with attractive resting and breeding grounds. No amount of tinkering with reproductive systems will change this, so it appears to me that the population of
Birding at the National Zoo
Among the many options available for birdwatching in Washington, D.C., Kenilworth Aquatic Gardens, Rock Creek Park, and the National Arboretum have proven the most consistently satisfying, with East Potomac Park and Roosevelt Island not far behind. However, the District contains a number of other places to watch birds. One such place is the National Zoo. That is where I took a short walk early this morning.
A zoo is not the first place that comes to mind when one wants to go birding. Certainly the captive waterfowl, cranes, pelicans, and eagles with shorn primaries are not "countable." But because of the heavy vegetation and easily available food sources, quite a lot of wild birds can be found among the cages in all seasons.
In summer, the main draw for birders at the National Zoo is a colony of black-crowned night herons that nest around the bird house. Some nests are placed on top of the old flight cage for captive eagles, while others can be found in the trees. The night-herons that roost here are quite tame. Juveniles will sometimes come down and stand in the ponds not five feet from the path; today I had a close look through my binoculars at two youngsters sitting on top of the flight cage as they peered down at me. Further along the trail, adult night-herons foraged in the crane enclosures. The adults, too, showed little fear of me. One flew out of the enclosure into a tree almost above my head, so that I got a close look at its red eye and the long white plumes that trail from the back of its head. This bird kept an eye on me as I took in the details of its plumage through binoculars. About a dozen more adults could be seen in the trees around the bird house.
The second reason to bird at the zoo is for a section of Rock Creek that passes along one side of the zoo. Because the road that parallels the creek for most of its length goes into a tunnel, the path here is much quieter than it is beyond the zoo in either direction. This section of the creek tends to be better for birding during the winter than during the summer. In the winter the creek remains open while other bodies of water in the area freeze, so that large numbers of mallards and wood ducks, joined by smaller numbers of other waterfowl, concentrate here. Today those crowds were not present, but I did see one wood duck family - a male and female with eight ducklings. Along the path I also encountered tufted titmice, an eastern wood-pewee, and an acadian flycatcher. The latter was detectable only by its wee-seet! call, which I imagine as a sort of sung checkmark. It was a pleasant birding session on a cool morning.
Thursday, June 23, 2005
Birds and the Land Rule Changes in the West
An article in yesterday's Christian Science Monitor outlines changes in the rules affecting ranchers whose cattle are having an adverse ecological impact. When herds of cattle are causing damage, their size must be reduced. Under the new rules ranchers can delay reducing their herds up to five years after the damage is discovered.
Giving extra time to ranchers is not in itself a bad thing. Land use rules need to address a variety of different interests and represent a balancing act of sorts. Many of the smaller ranchers are operating on marginal profits and need an extra boost from the federal government from time to time. What is bothersome, to me, is that the administration continues to distort or ignore scientific research that contradicts their agenda. Here is the director of the Bureau of Land Management:
Kathleen Clarke, director of the US Bureau of Land Management (BLM), which oversees 261 million acres of federal land in the West, says the new regulations "will produce long-term rangeland health benefits." These include more vegetation along stream banks, which will reduce soil erosion and provide more wildlife habitat, says Ms. Clarke.This statement flies in the face of both research and common sense. Overgrazing by cattle herds has long been known to reduce the amount of vegetation and increase erosion, not the opposite as Ms. Clarke claims.
It is especially jarring in the light of a recently-released study that attempted to discover the causes for the decline among birds that depend on grasslands for breeding. As the New York Times reports, scientists in Scotland and Spain studied meadow pipits in grassland plots with varying numbers of grazing sheep. Pipits in areas with heavy grazing tended to produce smaller eggs - and thus fewer viable offspring - than pipits who nested in areas with light grazing. This shows a clear impact upon breeding birds in areas with heavy grazing. Whether or not the new grazing rules will increase wildlife habitat, which is debatable, they will do little to promote biodiversity.
Tuesday, June 21, 2005
Kenilworth Aquatic Gardens and Park
This morning I took a birding trip to Kenilworth Aquatic Gardens and the adjacent Kenilworth Park. As befits the first day of summer, the water levels were especially high today, so much so that the gardeners had pumps running in several places to avoid flooding in the waterlily impoundments. The beaver dam was entirely covered with water. Of course this meant that there was little to see out in the marsh. One can occasionally see shorebirds out on the flats, but there were no mudflats to be seen today, let alone shorebirds. Common grackles were the dominant species today, and their constant movement and chatter proved distracting as I was looking for other species.
Right at the entrance I was greeted by a brown thrasher standing out in the open among the hollies near the parking lot. Once inside I heard a black-and-white warbler and saw a small group of blue-gray gnatcatchers, a small but hyperactive species. A green heron flew over the impoundments. After that things settled down. I heard common yellowthroats and indigo buntings as I approached the marsh, and passed within feet of a great blue heron standing stock-still in an impoundment.
The boardwalk and overlooks presented little aside from some eastern phoebes. This species seemed to be in relatively high numbers at the aquatic gardens today. I got a nice long look at one posing on a boardwalk railing, and later saw pairs wheeling playfully over the waters of the marsh. They were joined by numerous tree swallows and barn swallows, both of which breed there. The marsh is stocked with nesting boxes for such species. These boxes are carefully monitored by the NPS staff.
The river trail, which curves around the marsh and goes out to the tidal inlet, presented a few more nice finds. My first glimpse for the year of a northern parula came at the start of the trail. I had heard them before but not seen them, because they are hard to spot but have a loud and distinctive call, like a zipper being pulled up. I finally got to see an indigo bunting instead of just hearing them. A prothonotary warbler, unusual for D.C. but in proper habitat, called several times from the swampy wooded area between the trail and the nursery buildings. As I walked the portion of the trail that parallels the river, I could hear a pileated woodpecker call, and shortly afterwards one flew across the path on its way across the marsh. Soon I also heard the distinctive chick-per-ee-o-chick of the white-eyed vireo in more or less the same area where one was breeding last summer.
The best bird of the day was at the end of the trail. There I heard a call that I first tuned out as an alternate white-eyed vireo. But after listening to it for a few minutes I realized it was something different. When I got home and had a chance to listen to my recording, I confirmed my hunch that what I heard was the ritzbew of a willow flycatcher. This was a life bird for me, and brings my life list to 248 species.
On the way back towards the entrance, I spotted a wood duck sitting on a log in the marsh. After that I had no new species in the gardens for the day. Usually when I am done in the gardens I just walk over to the Deanwood station and head home. But today I wanted to check out some good sightings that had been reported from Kenilworth Park, just down Anacostia Avenue from the aquatic gardens. So I walked down and started walking towards the meadow area, where the birds had been found. Along the way I noted an eastern kingbird. As I came to the crest of the hill, I saw about a dozen police cars parked in a line in the gravel parking lot, with another dozen streaming in the entrance. Then a helicopter swooped low over the field. At that point I decided that my birding day was pretty much done. I will have to give that park another try soon. The species reported would be a lifer and a D.C. first for me, so it would be worth another shot, I think. I want to take some photographs of the waterlilies anyway, and it looks like we are near the best time to do that.
Today marks the first day of summer according to the astronomical calendar. Appropriately enough, we are experiencing temperatures a good deal higher today than during the past few days. (Once we hit June, I am thankful for any cool spells we get in D.C.) If you like evening walks, today is the day to go for one, because darkness will fall later today than on any day until this time next year.
Many experience the start of summer on a different date than the one marked on our calendars. For those of us involved in academics, summer really begins on the day the school year or semester ends - mid-May for colleges and universities, and mid-June for elementary and high schools. Memorial Day is frequently referenced as the unofficial start of summer, especially for beachgoers.
From a birding perspective, summer begins when spring migration stops, and ends when fall migration begins. Of course this varies greatly according bird families and individual species. Some species of shorebird that breed near the Arctic Circle are already preparing for their return flight to South America, even as other birds are still breeding. But broadly speaking, major migratory movement ends in late May, and will pick up again in mid-August. Between those dates is summer for birders.
I find summer a difficult season for birding. On the one hand, there are a lot more birds around during the summer than during the winter, and those that are here are in their colorful breeding plumage. But the season presents obstacles despite the increased leisure time. For one thing, it is hot, and here in Washington we have a heavy dose of humidity added to make a sticky mix without much relief. As much as I love birds, the thought of tramping around in hot weather is not appealing to me; I much prefer fall and winter weather. Leaves make it much harder to see the birds, and as the summer wears on they gradually stop singing. I can still come back from a summer walk with a decent species list, but each one will be hard-fought and there will be long stretches with no evidence of birds at all. So I approach this season with a degree of ambivalence. Still, a bad day birding beats a good day working.
Saturday, June 18, 2005
How I got started birding
It is hard to pinpoint a time when I first became interested in birds. I suppose I always have, in a way. When I was young I had bird books and went on lots of nature walks. My mother kept bird feeders that attracted multitudes of birds, including the occasional hawk. And in college and beyond I would make note of birds I had not seen before, and I would always look them up. I remember the first time I saw a brilliant blue indigo bunting, but I made no note of the date or location.
I did not become really excited about birding as a hobby until the summer of 2003. After a vacation during which I saw several bird species I had never seen before, I resolved to start getting out to DC's parks more, to get more exercise and to see what natural phenomena could be observed locally. On my first trip, an early morning foray to East Potomac Park in late July, I spotted a woodpecker clinging to the side of a tree. Like most woodpeckers I had seen to that point, it had a black back with white spots and a light belly. After closer inspection I saw it had a yellow belly - it must be a yellow-bellied sapsucker! I went home and checked my Sibley, and in my initial naiveté, I neglected to notice that juvenile downy woodpeckers may also have a yellow belly, and that a sapsucker sighting in July would be highly extraordinary in my corner of the world. In retrospect, this bird was almost certainly a downy woodpecker, but I have held onto this memory. First, the idea that I could see birds I had never seen before right here in this city excited me, and encouraged me to go out and look for more. For this I am thankful. Second, I keep this example in mind when I am too quick to identify a bird or stretch a sighting. A second and third look can do much to prevent misidentifications.
I find it funny that my initial excitement and involvement with birding was spurred in part by a misidentification. Since that time I have seen plenty of other yellow-bellied sapsuckers; they are plentiful in the Washington area during the winter months. Later, when I became wiser about expected bird ranges, I deleted that "first" sighting from my life list and replaced it with another YBSA sighting at the right time of year.