Thursday, September 10, 2015

Ornithology Lab, September 9

This is the second installment in a series of weekly posts for my ornithology class at Ohio University. We go out in the field every Wednesday (weather permitting) to do some birding and bird banding. One of our assignments is to write a blog post about each of these field trips, which is what this series will be about.

First Post: September 2

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An Eastern Wood-Pewee, one of the migrant species that was still singing at The Ridges. This photo was taken at Old Woman Creek in Erie County this past May.

It was another early morning at 6:45 AM. This week we were at The Ridges, Athens County, once more. It was yet another warm morning, with temperatures in the high 60's (which quickly climbed into the 70's) and near 100% humidity (dew points between 68 and 70 degrees). Haze filled the otherwise cloudless sky, and some patchy fog hung about in open areas. Put shortly, it was a muggy and still morning. I've been eagerly awaiting for it to feel like Fall, but it appears I'll have to wait a bit.

Sadly, it was yet another bad day for Fall migration; southerly winds for the past couple days have held down what migrants we've had in the region and prevented more waves from coming through. For you birders out there who want to know if a day has the potential to be good or not, a great tool to utilize is Cornell University's BirdCast. During Spring and Fall migrations, they give weekly outlooks, including regional outlooks, on what days seem to be good for birding, and what species will most likely be on the move. For an example, you can check out this week's outlook here.

I mentioned southerly winds holding migrants back, and I'll explain that concept a bit more, using BirdCast to help. The majority of songbirds (Warblers, Sparrows, Vireos, etc.) migrate during the night, which might surprise many of you (I know it surprised me when I learned!). Essentially, the birds take off at dusk, fly all night, and drop into a patch of good habitat in the morning. During the day they try to stuff themselves with food and rest, preparing for another full night of flying. During Fall migration, many songbirds are coming from their breeding grounds in Canada and the northern US and are trying to get to Central and South America to spend their winter. As a result, it is a huge energy-saving advantage if the wind is helping push you along. For this, the birds need northerly winds (winds coming from the north and blowing toward the south). If faced with southerly winds, many songbirds will simply stay put because it isn't worth the energy expenditure to try and fly against the wind. So to have a "good" migration day, you want to look for a morning where there were northerly winds overnight in your area/state. Northerly winds overnight should mean there are hundreds of hungry, tired migrants in the forests around you. 

Map courtesy of The Cornell Lab of Ornithology.

Now is where BirdCast comes in to help. Pictured above is a map of the wind directions predicted for Wednesday morning at 2:00 AM (last night). This is in the middle of the night, which is exactly when songbirds are migrating. If we look at Ohio, we can see that the entire state is covered by southerly winds. That means that the migrants north of us will mostly be staying in the north. These conditions make for a "bad" day for birders and bird banding.

Regardless that it was a bad migration day overall, we ended up observing and mist netting more species than last week, which was a hotter and overall more miserable day. This time we set up nets in 7 areas. I made a quick breakdown of the area, which you can see above. The short white lines represent the nets. As you can see, we set up the nets in a variety of habitats. This ensures that we get a wider range of possible species, as different species exploit different habitats. We had 2 nets set up in dense shrub habitat, 4 nets set up in young scrubby forest, and 1 net set up by a pond. Due to area and time constraints, we can't set up any nets in the deciduous forests with more open undergrowth. It's also important to note that most bird species, while having a preferred habitat, will cross through different habitats to find better food sources, especially in migration. For example, we had a foraging flock of Carolina Chickadees that came from the open deciduous forest in the top right corner of the photo, which moved down across the scrub forest directly below, and then moved over into the edges of the lawn area. By covering more ground, the chickadees have a better chance of finding a good food source. Also, since breeding season is over, the chickadees don't have to worry about territories for the time being. The chickadees formed this foraging flock in order to maximize their chance of finding food (more eyes means more ground covered in less time) and to maximize their chance of seeing any potential threats before it's too late (such as seeing a Cooper's Hawk fly in).

The first bird we netted was a young male Northern Cardinal. It was in the same area as the adult female that we netted last week. Later we caught another female in the same area (who didn't have a band, so it was different from the female last week). I've also seen a male individual in the area. Northern Cardinals will form foraging flocks in the winter, and it seems like we have the start of one forming. It will be interesting to see if we eventually get recaptures every time we go out.

The second bird we netted was a female Common Yellowthroat, a species of warbler. This was our second warbler species we've banded so far in the Fall, and hopefully there are many more to come.

The third bird that flew into the mist nets was another Northern Cardinal. This individual was a juvenile, as the black beak told. Cardinals will have orange beaks when they reach adulthood.

An adult male (left) and adult female (right) Northern Cardinal. Notice the orange beak on the female; although immature males have plumage like a female, their beaks are black/brown. Both photos were taken in Pickaway County this past Winter.
In keeping with the cardinal theme, the fourth bird was an adult female Northern Cardinal. This was the individual I mentioned along with the first cardinal from today.

The last 3 birds we had were all caught in one net, and all during the same period. We had set up a net on a pathway between two areas of vine-covered shrubs with a a few trees scattered about. This is perfect White-Eyed Vireo habitat, and we were lucky enough to catch not only one, but three individuals in one go.

An adult White-Eyed Vireo. This was taken along the Nature Walk trail at The Ridges during Spring Migration.
One of the White-Eyed Vireos was noteworthy - he had already been banded, and not by us. All 3 individuals were "Hatch Year" individuals. This simply means they were all born this past Summer. So the one that was banded had not only been born within 4 months or so ago, but had also been netted and banded during that time. We then recaptured it while it was migrating south. One of the cool things about bird banding is learning about recaptures; if you can read the code on its ankle band (by either photo or having the bird in hand), then you can look that code up in the bird banding database to learn where that individual had been previously caught, who banded it, and other assorted information. Sadly we haven't been able to look up the code for that one yet, so I can't say where it had been previously banded.

Here is my personal list for the day, which includes all the birds I saw/heard from 7:00 AM to 11:30 AM:

1. Turkey Vulture
2. Rock Pigeon
3. Mourning Dove
4. Ruby-Throated Hummingbird
5. Red-Bellied Woodpecker
6. Hairy Woodpecker
7. Pileated Woodpecker*
8. Eastern Wood-Pewee*
9. White-Eyed Vireo
10. Yellow-Throated Vireo*
11. Red-Eyed Vireo
12. Blue Jay
13. American Crow
14. Carolina Chickadee
15. Tufted Titmouse*
16. White-Breasted Nuthatch
17. Carolina Wren*
18. American Robin
19. Cedar Waxwing
20. Common Yellowthroat
21. Magnolia Warbler
22. Wilson's Warbler (New for my Athens County list)
23. Eastern Towhee
24. Northern Cardinal
25. American Goldfinch

Note: * means "Heard Only"

A Tufted Titmouse, one of the species we heard today. This adorable individual is from Pickaway County.
Overall, this was a pretty good day. We had a decent number of birds banded, and I got to see my first Athens County Wilson's Warbler. There have been a few peculiarities so far though. We haven't heard or seen a Gray Catbird yet, and there's plenty of perfect habitat for them where we band. eBird doesn't have sightings dropping off in Ohio until late October, so I'm surprised we haven't seen any in such a good habitat. We have also been missing Eastern Bluebirds, a relatively easy-to-find bird at The Ridges. Song Sparrows have also been missing so far. Of course, it is only our second week out at the same location, so we might have just missed any in the area, but I'm still surprised we've went 9 hours of birding total without seeing any of those species in an area where I've seen them previously. I'll just have to keep my eye out even more.

Thanks for reading!

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