Thursday, November 27, 2014

Bird Banding

Two weekends ago on the 15th I woke up as the sun was rising, donned four layers, and made the short trek to The Ridges in the brisk 16 degree weather. Why? To go bird banding, of course! One of the Ohio University graduate students specializing in ornithology has been setting up banding stations at The Ridges, and he invited the OU Wildlife Club to see what banding is all about. Sadly, the early time and the cold weather turned most people away. In the end, only me (the secretary), Alayna (the president), Olivia Brooks (who runs the Twitter account Wild Earth), and one other member showed up.

For those of you who've never been, The Ridges is a large tract of land now owned by Ohio University which sits on the outskirts of the city of Athens in Athens County. The main point of interest is the old "insane" asylum, but there's also dozens of acres of forests and grasslands with miles of hiking trails, which I've partially covered before. The graduate student set up a total of three nets near the Nature Walk Trail in order to catch and band birds. What exactly is bird banding though? Well, bird banding is where a certified bander will place a small metal ring on the leg of a wild bird that was caught in a "mist net." Each band has a unique number and that number, along with morphological data of the bird, goes into a giant database. The idea is to be able to mark an individual, recapture it at a later date, identify the individual, and then gather more data. On a large scale, this process helps us learn more about migration routes, morphology, age, and various other information.

So what did we catch that day? I'll start off with this Tufted Titmouse, Baeolophus bicolor. This common backyard species is a part of the tit and chickadee family know as Paridae. If any of you are birders, you're probably well-acquainted with these guys. Many of the species in Paridae are known to form medium-sized flocks during the winter; right about now you'll see flocks of chickadees moving throughout areas searching for food. The Tufted Titmouse is a bit different. They actually don't form winter flocks; instead a breeding pair will continue to stay on their summer territory and search for food. Many times one of the hatchlings from the previous summer might join them, as well as other random juveniles from the area. Occasionally they will join those chickadee-based flocks. These flocks have a very hierarchical nature, and the Tufted Titmice, when they're part of those mixed winter flocks, will assume the most-dominant role.

A closer look at the feet reveals extremely long, and very sharp, talons. Tufted Titmice are denizens of forests, particularly forests with dense canopies as these provide excellent cover and foraging opportunities. A large part of a Tufted Titmouse's diet is arthropods. These large, sharp talons help them grasp the bark of trees as they search it for insects, spiders, and the like. I'm always struck by just how dinosaur-like birds' legs are; it really makes sure you're reminded of their reptilian origins.

Carolina Chickadee
Also in the family Paridae is the well-known and much loved Caroline Chickadee, Poecile carolinensis. If you know nothing about birds, you have still probably heard about the chickadee. We have two chickadee species here in Ohio. Identification between these two species is difficult due to their very, very similar appearance, but typically this isn't a problem due to the fact most people are only in one of the species' range. If you're in Athens, for example, you know 99.9% of the chickadees you'll see are Carolinas. But Ohio, as I mentioned previously, has both species. Generally, to the north is the Black-Capped Chickadee, and to the south is the Carolina Chickadee. But this also means we have a dreaded transitional zone between the species. This roughly exists along the Lima-Mansfield-Canton line across the state. What makes this line even worse for birders, but cool for scientists, is the fact these two species will even hybridize within this zone.

Carolina Chickadee

Carolina Chickadees are very intelligent and interesting birds. Many times this species will act as "alarms" for other songbirds in the event of a threat coming into the area. Upon sighting a threat, Carolina Chickadees will many times give a buzzy "chick-a-dee-dee-dee" call, which is where they get their name. Interestingly, studies have found that the Carolina Chickadee tailors that chick-a-dee call to the severity of each threat. For example, one study (Soard, C., and G. Ritchison. 2009) found that for lower threats (such as a Red-Tailed Hawk, which would typically not hunt chickadees), Carolina Chickadees gave a call with more of the introductory "chick" notes than the buzzy "dee" notes. On the flip-side, predators posing a significant threat resulted in the chickadees giving a call with more of the "dee" notes than the introductory "chick" notes (if there were any "chick" notes at all.) If you're interested in that study, you can download a PDF from this link.

Female Northern Cardinal

The largest bird we caught that day was this female Northern Cardinal, Cardinalis cardinalis. This bird, also called the "redbird" by some, is a very common species in Ohio. In fact, it's even the state bird (along with six other states). With most songbirds, only the male sings. Bird songs are employed by males to mark territories and to attract mates. With the Northern Cardinal, the females will also sing. While songs vary, both sexes will sing the same types of song.

Song Sparrow

The final bird we caught that morning was the ubiquitous Song Sparrow, Melospiza melodia. These are one of my favorite birds and they have one of my favorite songs. Song Sparrows don't actually have a "set" song; there's a whole range of bits and pieces that the Song Sparrow will string together to make one individual song. Many times a song will have certain parts which almost all use (like the 2 or 3 introductory notes which most songs start with), which allows birders to quickly know what they're hearing is a Song Sparrow, even though it might sound nearly completely different than any they've heard before. Song Sparrows will actually learn the songs of neighboring individuals and add them to their repertoire. An individual can know over a dozen different songs, many times with hundreds of small variations on those general songs. An individual can also improvise and tweak his songs and his learned songs to create new songs, which other neighboring individuals can learn and tweak themselves. As you can see, the Song Sparrow's use of songs is a highly complex endeavor. What's even more interesting is the effect they have on females. As I stated previously, males will use songs to attract females. Most of the times the females are attracted to the male's performance of a set species-wide song. With Song Sparrows, studies have found that females are also attracted to the male's ability to learn, which is reflected by the number of songs he knows on top of how well he actually performs them.

Bird with Tick

When the graduate student was taking measurements of the Song Sparrow, I noticed something a little odd. It looked like a tick was on the neck, and sure enough upon checking there was a blood-engorged tick attached to the neck. This tick is probably Ixodes brunneus, also called the Bird Tick. This is, as most ticks are, a bad thing. Not only do you have a blood sucking parasite, but these birds can contract a condition known as tick paralysis from these ticks. Many Ixodes tick species have a substance in their saliva which upon injection to a host will slowly paralyze that host. Eventually this can lead to death. We decided to remove the tick, so hopefully the sparrow will be fine.

That's it for this long post. It's currently Thanksgiving as I write this, and this has been the first time in a few weeks that I've had to sit down and actually write. Finals week is currently only two weeks away, so once again I'll be tossed into the college craziness when I head back to Athens this weekend. I've been slacking on posts recently and hopefully with break I can catch up. Thanks for reading!