Today, you guessed it, I learned how to sex a bird (at least during breeding season). The morning started at Tremont at 6am to set out 10 mist nets to capture migratory song birds as part of a MAPS (monitoring avian productivity and survivorship) research project conducted by Tremont. After opening the nets, we had to make rounds every 40 minutes to check for any birds caught in the nets. Each captured bird is then banded with a unique band with a 4 digit site identification number and a 5 digit bird identification number, weight is measured, sex is determined, and age is estimated. If there are no visual distinctions of sex for a bird, gender is determined (during breeding season) in one of two ways. Male birds will have a swollen cloaca (the cloaca is an all-purpose oriface... it's used for both breeding and, um, waste disposal--so you can imagine why it is swollen). Female birds will have what is called a brood patch, a featherless patch on the chest where they will have plucked their breast feathers in anticipation of a nest full of eggs. The bare chest will allow the mother bird to drape the remaining breast feathers around the eggs, drawing the eggs closer to the skin for added warmth, and then holding in the warmth with the surrounding feathers. Pretty neat adaptation. There are, however, two enlightened, feminist birds who don't follow this pattern in East Tennessee--the woodpecker and the veery, in which the male has a brood patch. Age is estimated by skull development and feather molting patterns.
During the first net run at 7am, we netted a Chipping Sparrow. At the 7:40 run, we netted 2 Acadian Flycatchers (ACFL) (1 was a recapture from a previous banding day) and a Louisiana Waterthrush (LOWA). I got to release the the LOWA :)
The 8:20 run was empty, but at 9 we netted 2 LOWAs (1 recapture). We also netted 2 LOWAs at 9:40. At 9:40, we got to practice bird handling techniques, learning the 2 main holds--the photographer's grip and the bander's grip. No birds were netted between 10:20 and 12:20.
RANDOM TIDBITS:
Many bird species have the defense mechanism that the hatchlings poop in a fecal sack--a wad of poo encased in a membrane that the parent bird flies away with to deposit away from the nest so as not to attract predators.
Good tasting caterpillars are neat eaters. So birds will have trouble detecting yummy caterpillars, the good tasting ones eat in straight lines, eat in patterns, or eat and then chew the stem of the leaf until it falls to the ground. On the contrary, crummy tasting caterpillars eat big honkin' holes in leaves.
The song of the Acadian Flycatcher sounds like "Petes eat, Pete's eat"
The song of the Tufted Titmouse sounds like "Peter peter peter"
The Carolina Wren says "Cheeseburger cheeseburger cheeseburger"
FYI: During breeding season, anyone can volunteer to help on banding days as part of their Citizen Science program. The next banding day is July 4th. If you want to head to Tremont at 6 on the 4th, let me know and I'll fill you in on what you need to do to go.
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