Cock-of-the-rock rodeo!

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One of the most interesting features of Las Tangaras is the Andean Cock-of-the-rock (ACOR) lek.

The Andean Cock-of-the-rock is a type of bird called a cotinga. It is a lekking species, which means the males conduct competitive mating displays in a common area. Las Tangaras happens to have within its borders one of the largest known ACOR leks in the world.

A lot of things aren't known about the birds displaying however, and how it relates to reproductive success. For example, do the same birds display at the same lek every day? Do birds that are related to each other coordinate their efforts? And so on.

The birds could be caught and banded like other birds but it was impossible to distinguish them in the field by the small metal bands on their legs. Dusti hoped to put some special colored plastic bands on the birds' legs, so we could afterwards distinguish individuals during their displays. First, though, we had to catch a bunch of ACOR males.

The lek is high up on a wooded ridge, in fairly steep terrain with dense vegetation. The birds gather twice a day, after dawn and again later in the afternoon. They make a huge variety of whooping and screaming noises in the course of their displays, bobbing and flapping on exposed branches. The birds will also physically attack each other with their legs. At the height of the diplays there might be as many as 20 birds in the immediate area, many of them displaying at once. According to Dusti this goes on at some level 365 days a year (being on the equator the location sees little seasonal climatic variation).

Dusti's idea was to surround the lek as best we could with nets, mostly on existing trails. Eric and I were assigned to the a.m. "rodeo", which turned out to be a bust. Early on we heard two whoops from Mauricio on a lower trail. Pascual went down to help but came back empty handed, it turned out two ACORs had crashed into a net near Mauricio but both had escaped through holes. We got a total of one hummingbird all morning, in all the nets.

After the birds had settled down (about 9am) we rolled up the nets and went back to the casita to get more. Eric and I went back up the ridge with Pascual, Mauricio and Giovanny to put them up. Pascual seemed very motivated and we put up a couple of the new nets on very difficult terrain (steep, overgrown) in the middle of the lek area.

During the course of the work Giovanny kept baiting Mauricio, calling him "puerco". After a while Giovanny asked me how to say it in English ("pig"). For the rest of the day Giovanny called Mauricio "pig". Aqui esta, pig! Muy bien, pig!

Giovanny also asked me how to say "my wife's sister" in English (presumably he meant sister-in-law). I got the feeling there was some type of joke at Mauricio's expense but Giovanny couldn't explain it to me.

The PM ACOR rodeo looked like it was going to be as unproductive as the morning. Everyone was so interested that the entire group came up. Dusti was concerned because the birds seemed to have dispersed somewhat, as if all the activity and disturbance of their lek had made them move elsewhere. She decided we would try one more time the next morning, then take down the nets.

Very late in the day, Pascual finally got one bird in a net. There was quite a bit of commotion, many pictures taken, etc.

Then, as darkness fell, Mauricio came back with three!

Birds seen today:

Plumbeous pigeon
Dark-backed Wood-Quail


I also have some type of thrush in my notes, but it isn't clear what species.

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Photos

ACOR displaying at the lek
My photographic skills don't do these birds justice. They are the most intense blood-red color, with black and some white on the lower body.

Mauricio coming back with three ACORs at once
He had two in the bags we used for carrying the birds, and one in his hand!