Most of our familiar birds court potential mates only at specific times of year. This is why spring is such a melodious season in many places: the male songbirds are all singing for their mates. Male pigeons, however, seem to court all the time. It’s below freezing and snowing? Why, what a great time to puff up and bow and coo at the ladies!
Well… yeah. What’s your point?
This seems strange because we expect courting birds to breed soon after a successful courtship. Yet pigeons court in weather that seems like it would be terrible for breeding. What are these pigeons up to? Are the males really trying to convince the females to lay eggs in mid-winter?
Male Golden-winged Warbler. Photo by Mark Peck*
This story begins when Streby et al. (2015) decided to track Golden-winged Warblers during their annual migration. We know that lots of birds migrate, but for most of them, we know surprisingly few details about that migration. Often we know generally where they go (to a specificity of, say, “somewhere in South America”) but not exactly where; rarely do we know what paths they take to get between wintering and breeding grounds. This kind of information is especially important for birds of conservation concern, since to protect a migratory population, you need to protect its wintering grounds and migration route as well as its breeding grounds.
The researchers relied on technology to tell them where the warblers went when they migrated. There are several different ways to track animal movements; in this case, researchers used light-level geolocators, which record the amount of light hitting the geolocator. Collected over time, these light intensity measurements allow researchers to calculate where the geolocator was, based on things such as day length. This location information isn’t as accurate as the data you would get from a GPS logger, but the light-level geolocators have a big advantage over GPS loggers: they can be much smaller, so you can put them on tiny birds like Golden-winged Warblers. A Golden-winged Warbler attached to a heavy, clunky GPS logger would not be migrating anywhere.
California is in the middle of a severe drought. Winter is the rainy season here, and the last two winters weren’t rainy. The drought’s major human impact has been agriculture-related: California grows a hefty portion of the US’s fruits, vegetables, and livestock, all of which require water. The drive to my field sites takes me through the agriculture-heavy Central Valley, and the drought was clearly apparent this summer. The fields were all cracked dry earth and yellow grass, with the rare irrigated green square standing out like artificial turf. One afternoon late in the field season, a light rain sprinkled as we drove through the valley, and we rolled down the windows and cheered.
The Central Valley is thirsty.
Concerns over agriculture affect everyone; but beyond them, and more personally, I can’t help seeing the drought through the lens of a field biologist.
I have colleagues who slip and slosh through mud all summer to study Black Rails—or who hope that there will be mud to slosh through, anyway, because the small, secretive Black Rail relies on the existence of marshes in which to hide from predators and hatch its comically large-footed chicks. Less rain means fewer and smaller marshes for the Black Rails.
I’ve been meaning to write about this topic for a while—now xkcd has beaten me to it:
Oh, well. Since the comic doesn’t actually answer the question, I’m hoping you’re all still interested! (Also, at the end there will be a bonus discussion of ant rain. Yes, ant rain. You won’t find that on xkcd!)
The season of the summer disaster movie is upon us: Godzilla is stomping San Francisco, and I’m sure we’re all eagerly anticipating the premiere of Sharknado 2. To liven up the cinemas a bit, as a relief from the overabundance of sequels (I mean really, Sharknado 2!), I would like to propose a new genre mash-up: the animated talking birds disaster movie. It would be like those dancing penguin movies, or the solemn-looking owl movie (I have seen none of these…), plus disasters. The first one could be called Hailstorm!
It would not be a children’s movie. It would be terrifying.
It hailed on us a few days ago for about half an hour. The hail was mostly small, not larger than 1 cm in diameter, and the only animal reaction I saw was a decidedly alarmed chickaree—although to be fair, chickarees almost always look alarmed. I saw no evidence of damage afterwards; all of the junco nests we were monitoring weathered the storm just fine.
You know the hail isn’t too bad when you can safely hide from it in a tent.
But sometimes hail is a sharper-fanged beast.
Two weeks ago, it rained on us for a solid 22 hours. (Which, I discovered, is exactly the time it takes for puddles to start forming inside my tent.) So when it got grey and thundery at the beginning of last week, I jumped: “We’ve got to process this junco quickly! Take down the nets! We have to get back to camp to cover the firewood!”
Of course, it didn’t rain. The next time it got grey and thundery, I jumped less: “Let’s take down one net and keep this one. Tell me if you see lightning.” It didn’t rain.
The third time it got grey and thundery, I didn’t jump at all. Then it actually started raining—but I really wanted another junco. So we caught a male in (very light) rain and banded him under a tree, naming him KKRA, which sounds a bit like the thunder that was rolling in the distance.
KKRA, who has one white feather on his cheek