A study by researchers at an institute in Russia, reported in a Reuters article, says “Eurasian reed warblers captured during migration and then dumped 1,000 km (620 miles) off course were able to find their way back to their original route, according to a study suggesting some birds can truly navigate.” And later: “We have experimentally shown beyond reasonable doubt that long-distance, intercontinental avian migrants can correct for east-west displacements during their return migration in spring,” Chernetsov wrote. “This means that they can determine geographic longitude, even though we do not currently know how they do it.”
Archive for January, 2008
One of life’s little mysteries has been solved: the distinctive high-pitched “chirp” that a male Anna’s hummingbird can make is generated by the tail feathers, it’s not a vocal sound at all! BBC News has an article about it, with a link to the sound (worth hearing) and a poor-quality, far-away soundless video preceded by an ad (not worth watching). By the way, this is not the chip-chip-chip sound, which is indeed a vocalization, it’s a special CHEEP that the hummingbird makes only at the bottom of a steep dive.
Posted under local wildlife
At its peak, the fall run has numbered hundreds of thousands of fish, exceeding 800,000 in some years. But this year the preliminary count has put the number at 90,000 adults returning to spawn in the Sacramento and San Joaquin rivers and their tributaries. During the past decade, the number of returning fish has never fallen below 250,000.
There’s a fair amount of squabbling about the causes of this big decline: is it the low water releases from the dams on rivers where salmon spawn? Is it the diversions of water around the Delta through giant pumps, which kill some young salmon and move others to areas where they’re more vulnerable? Is it pollution in the Bay? Pollution in the ocean? Etc., etc. Hey, how’s this for an idea: it’s all of the above! 10% here, 20% there, pretty soon you’re talking about a 70% decline. There doesn’t have to be a single cause.
The Altamont Pass wind farm, just east of Livermore, has over 4500 turbines (a.k.a. windmills) and was, at one time, the largest and highest-power-producing wind farm in the world. Unfortunately, the specific location and design of some of its turbines also makes it a blender for birds, and over the past 20 years it has probably killed over 20,000 birds, including hundreds of golden eagles and thousands of hawks. As part of a lawsuit settlement a couple of years ago, the wind farm operators agreed to make some changes to greatly reduce the bird kill: they would shut down some of the turbines during the winter (when kills are highest and power production is lowest), and would remove some of the less efficient turbines and replace them with larger, more efficient models that have been found to kill fewer birds. Sounds OK, but here’s the thing: they aren’t doing it! The San Franciso Chronicle had an article about this a few weeks ago. Oooh, it just burns me up.
The New York Times has a short article (free registration required) about the migration of Bar-Headed Geese between Mongolia and southern India, a distance of 3000 miles. That’s not remotely close to the distance record for a migration, but there is still something special about this particular migration: according to the article, “bar-headed geese hold the altitude record for birds,” [a researcher] said. “They migrate over the Himalayas, at 30,000 feet. That’s the height of jumbo jets.”
Posted under local birds
A “Big Year,” in birding parlance, is an attempt to see as many bird species as possible in a year. Expanding on the concept a bit, this year there are efforts in Alameda County and Contra Costa county for groups of birders to see as many birds in the county as possible. If you see something rare in these counties, you should definitely report it! The relevant links are here, along with some other contacts. As mentioned in a previous post, there is also an even bigger stretch of the Big Year concept, an effort to get visitors to Golden Gate National Recreation area to see as many endangered species as possible (not just birds), a great idea, check it out.
This is actually old news (from April last year) but what can I say, nobody tells me nuthin’: “