Featured paper: five warblers, lots of tornadoes, and a mystery

Male Golden-winged Warbler. Photo by Mark Peck*

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.

Continue reading

Advertisements

The sky is falling: birds and hail

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.

We hid in our tents.

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.

Continue reading