Cowbird husbandry

Solutions for trapping and studying cowbirds

Prior to joining the lab, neither I nor anyone in the lab had trapped or housed cowbirds. The older Schmidt lab work had been done in collaboration with David White, who was at the time located nearby, so when we were setting out on our own, there were a lot of new things to learn.

I came up with a few useful solutions for us, and maybe they would help you also.

Collapsable Funnel Trap

We didn’t have a location where we could have a trap open year round, but we were able to partner with the Marshak Dairy at the New Bolton Veterinary Facility. They happened to get plenty of cowbirds, but we needed a cage that would survive the elements, set up and break down easily, and be transported there (ideally in a minivan). Check out my design if you need something of this sort. (Alternatively, if you have the money, the Cage Builders do excellent work, and I highly recommend them.)

Printed “Phallabands”

We needed large bird bands that would be visible to the camera, but light enough to not bother the birds and easily painted. After several iterations, I managed to come up with something that was easy to produce and reliable. In theory these could work for any bird, and could be adapted to be smaller or larger. Traditional bird bands will likely be better for most scenarios, but if you need something huge, this is a good solution.

Homemade sound isolation boxes

Large metalic sound chamers are extremely expensive, and the excellent Ofer Boxes aren’t generally large enough for cowbirds. Based on the designs from accoustic solutions, and the well used Ofer boxes, I build a wooden box that functioned well for our purposes of playing sounds to cowbirds. A little labor intensive, but functional.

9-rack playback

We were severely space limited at Penn, and only had space for 2 of these sound isolation boxes. We initially used drink coolers, which worked well but were quite labor intensive in terms of housing. However, it occurred to me that we might not even need to isolate the cowbirds from eachother, since they were all hearing the same sounds simultaneously anyway. With that in mind I experimented with playbacks in traditional 9 racks and found those were successful for playbacks. I also wrote some code to run the playbacks, which is avialable on my github.

Cowbird food

We feed our cowbirds the modified Bronx Zoo diet, which we got from David White. It’s available here. Check out my instructional video here.

Aviary housing

This is part of a larger aviary project, but I’ve learned a lot about how to house cowbirds around electronics for computer vision. This is very specific information, but useful to think about if you’re housing birds around electronics.

Here is my shortlist of things we’ve learned.

1. Anything inside the cage is going to be perched on and pooped on. Outside is better.
2. Consumer microphones turn out to be pretty resiliant to being rained on. We decided against waterproof mics, and so far have no regrets.
3. Metal spikes are generally safe for birds, but there is a risk of their legbands snagging. They also only work for a short time. I would recommend against using them.
4. Coroplast is useful for everything, and can be used to discorage cowbirds from perching on things.

Nest boxes

Bird houses make perfectly good nest boxes for cowbirds, and can provide some extra control. Because I need to mount them on the outside of the aviary (for space, and camera reasons), I modified nest boxes from home depot to attach to the mesh. It’s a pretty easy solution.