There are a few studies out on the effect of cats on birds. Nearly all of them show a negative effect of cats on bird populations. I only came across a single paper by Courchamo and colleagues in 1999 that show a positive influence of cats and this is a modeling paper.
One of the more interesting studies was Crooks and Soule's investigation of the interaction between cats, birds, and coyotes. Where there are more cats, there are fewer birds. Where you have coyotes, there are fewer cats. By analyzing scat, they found that coyotes were eating cats and the assumption was that there were fewer cats eating birds. But were the cats actually eating birds?
A new study (link to press release) by the University and Georgia and National Geographic's Remote Imagine Department actually show cats catching birds and other animals. When I say show, I don't mean demonstrate through experiment, I mean there's video!
How many birds? Their estimate is 500,000,000 birds per year. I'm not sure how they included feral cats, which must kill "professionally" to stay alive.
Will be interesting to see where this gets published and the public reaction.
COURCHAMO, F., M. LANGLAIS and G. SUGIHARA. 1999. Cats protecting birds: modelling the mesopredator release effect. Journal of Animal Ecology 68: 282-292.
CROOKS, K. R. and M. E. SOULE. 1999. Mesopredator release and avifaunal extinctions in a fragmented system. Nature 400: 563-566.
Monday, August 6, 2012
Tuesday, July 31, 2012
Just add an urban environment!
- Impervious surfaces (roads and roofs work best)
- Breeding habitat for mosquitoes (ditches and sewer drains)
- Mosquitoes (Culex or Aedes)
- Simplified bird community (robins work best but you can substitute house sparrows)
- Mild winters followed by extended dry periods with periodic heavy rains
- Serves tens of thousands!
Kits are available
Just add an urban environment!
Tuesday, July 24, 2012
Sunday, July 22, 2012
How do you catch a bird?
This is the most asked question when I tell people what I do. Humans aren't exactly equipped to catch birds like a cat. This is particularly true for me - large, slow, and crazy-eyed. So how do we gets in our hands to study?
I don't stand still and just grab them....
I don't use a butterfly net...
I use a net like this:
Here's a close up of the net with a better background.
What the picture on the AFO doesn't show is that there is extra netting that sags below each trammel so that forms a long fold. Birds hit the net and fall into the fold. Here's a young house sparrow that I captured in the net. This bird was taken out of the net within 15 second. For the Marcellus project and the disease project, birds are taken out within seconds of falling in. If I'm setting up a string of nets, end-to-end, I check the nets every few minutes. I check more frequently when it's hot out to reduce stress on the bird (which reduces my stress).
Without mist nets it would be impossible to handle adult birds. We wouldn't be able to get DNA samples, blood samples to know if birds are being exposed to contaminants, band them to understand movements, populations, and behaviors.
Tuesday, June 26, 2012
|Box construction phase of 2011.|
|Typical box. About 1/4 of the boxes have thick "plastic" tops that I hope will make the boxes last much longer.|
|What we hope to get: babies! In this case Eastern Bluebird chicks! Cute, eh?|
|Last year's crew. With Amanda, Nipa (still with us!), Kelly (still with us!), Chris (still with us!), Nate (still with us!) and Becky (graduated)|
The Project Status
The good news
The project is currently running on all cylinders and much improved from last year. I have a full time field crew that is mostly Chris (college senior), Kelly (junior), and Anthony (senior). When I go out I get lots of help from my volunteers Matt (senior) and Colleen (junior). Instead of waiting until the end of the season, we've been getting the blood analyzed as it comes in with my lab crew Nipa (junior), Nate (senior), and Kevin (sophomore) with some help from Katie (junior), Tim (sophomore), and Adam (sophomore). I'll post a picture of everyone as soon as I can get them all together!
We have ninety-one nest boxes currently up and at various sites across eight counties in the northern tier (northeast quadrant) of Pennsylvania. At least twenty-seven are occupied and I suspect more will be as the season goes. Most of these boxes are occupied by tree swallows but we have one chickadee nest (successfully fledged) and one tufted titmouse nest at Lands at Hillside. We didn't take blood from this species since a they essentially represent a single sample and we would have no others for comparison. There are also a number of bluebird nests, which I am very happy about. I'm entering the tree swallow banding data and we probably have at least 50-60 babies banded!
We've also had zero predation! This was also true of my post doc bluebird project in Georgia. Could it be the poles the nest boxes are mounted on?
Because we may not have enough samples from the tree swallows, we're supplementing the data from nest boxes with mist net captures. Our target species are common yellowthroat, song sparrow, and Carolina wren. Song sparrows are our most commonly captured species. They are super-abundant and easy to catch. Common yellowthroats are much harder to catch and we have one or two captures of Carolina wrens. We will add red-eyed vireo and gray catbird because we catch so many of them. I'm just not sure how well they will represent surface water quality (more on this soon). We also captured (without trying) a number of other species including scarlet tanager, veery, and a number of warbler species. Very exciting!
Now the bad news
Our project was largely funded by a grant from Pennsylvania's DCNR Wild Resource Conservation Program and is now in the second year of its two-year funding. I recently was told that contamination issues associated with Marcellus Shale gas drilling are not part of this year's priorities. To see what they're funding, read this. This would be jaw dropping but - I better not say anymore!
The other large source of funding was through a grant from the Howard Hughes Medical Institute to Wilkes University. This is also puzzling since we did create a culture of undergraduate research at Wilkes University.
I also tried Crowdsourcing through RocketHub but this did not generate too much - makes me appreciate those that gave all that much more! These funding will largely go to camping fees when traveling to the sites that are more than 2 hours away.
Where to go from here
We will finish this season, which is turning out fantastic. I'm already scheduled to present our results in Vancouver at the North American Ornithological Conference. We will try to publish what we find and will, at least, turn in a report to DCNR, which will be publicly available. We can always apply for a mentoring grant but that may not cover all the expenses. So we'll see. I am pursuing other sources of funding.
Saturday, June 23, 2012
The Concrete Ornithologist
My career in ornithology started in the Amazon but funding availability led me to look at avian communities along an urban-rural gradient through the Auburn's Center of Forest Sustainability.
For the last couple of years I've been looking at a number phenomena along urban gradients including avian diseases, insectivory, and frugivory.
Most recently, my research team and I are examining if there is evidence of surface water contaminants from gas drilling making their way to terrestrial birds.
|Gas well outside Dimock, PA|
This is where I'll post my activities and other (random) thoughts. Enjoy the ride.