Raptors, Maybe

Tying up my California adventures with a bow, here's a music video the GGRO interns made to sum up our experiences in raptor research on the Pacific Coast.

A Hike in the Headlands

I've been pretty lucky to live in some amazing natural areas since graduating. I barely scratched the surface of all the parks and hiking trails within an hour of me in California, much less in my own backyard. The Marin Headlands, the national park that my house was in, has a ton of hiking/biking/horse-back riding trails. I got to know some of them quite well as they were a part of my daily commute to the office. However, there were a ton of trails that I never even got a chance to explore.

On one of my last days out there, I woke up to see a "weather alert" on my iPhone. I found this amusing because most of the country was getting pelted with snow and meanwhile, we were enjoying sunny, 60-degree weather. The alert, however, was for dangerous "wave conditions." I decided to check this out, while also exploring some of the unexplored trails in the Headlands.

Here are some of the photos I took of the waves at Rodeo Beach:

From the beach, I hiked up the trail towards Hill-88 and Tennessee Valley. As with all the trails in the headlands, this included some steep climbs, and all sorts of discarded World War II military apparatuses. I never did my homework regarding the human history of the area, despite the fact that we were counting hawks atop an old bunker, one of the many signs around the Headlands of the military history. On this hike, I passed a big (HUGE) gun, obviously out of use, but as a demonstration of the size of some of the artillery that was used in this area.

One of the banding blinds was located on a hill facing "Hill 88." I spent many a day, staring at that hill, and during this hike, I finally got a chance to check it out. What I found was a ton of abandoned buildings, again probably originally of military use, but now primarily serving as canvases for graffiti artists.

Of course, I couldn't go for a hike without paying a little attention to the avian life around. In addition to some of the usual culprits, I was pleased to see quite a few Anna's Hummingbirds. While eating my morning snack, I also watched an American kestrel hunting along one of the fences on Hill 88.

White-crowned Sparrow

Anna's Hummingbird

From the top of Hill 88, I hiked down a pretty steep trail for more than a mile into Tennessee Valley. It was a pretty quick hike from there to the Tennessee Valley beach.

Looking back up the hill I'd come down, I decided that I'd have to try an alternate route back to my house - it was pretty muddy and would have been tough attempting to climb back up that trail. The trail I took ended up giving me an awesome view of some of the nearby cities and their bizarre roads and houses, built right into the hillsides.

The final descent took me into Gerbode Valley, a trail that I'd hiked once before, to listen for owls with a group of visitors.

Like I said, I was pretty lucky to have had a chance to live in the Marin Headlands, a beautiful natural area (and amazing that it's so close to such a large city!) I will miss being able to hike around the lagoon, looking at ducks and herons, falling asleep at night to the sound of great horned owls and coyotes, and following ravens and a white-tailed kite to work on my bike each day.

Raptor Tracking

One of the research projects at GGRO that I got increasingly involved with during my internship involved a new and exciting piece of technology called a GSM tracker. Put simply, this is a small device we can affix to a bird. Recharging via solar power, the device will periodically send us the GPS coordinates of its current location, much the same way that text messages are sent cell phone to cell phone.

Of course, if the device isn't able to recharge (for example, if the bird is hanging out underneath dense vegetation or the bird preens a feather on top of the solar panel) the battery will die and we will no longer receive signals. Similarly, if the bird isn't in the range of a cell phone tower, we won't be able to receive the "text messages." Despite these occasional technological hic-ups, however, the technology provides us with a lot of useful information, namely the exact locations of where these birds are traveling. While band recoveries usually give us one location, sometimes two, with these devices, we can track the exact movements of these birds throughout their entire migration (which would be kind of creepy if we were talking about humans…).

I got a chance to see a juvenile, female red-tailed hawk get a GSM device affixed on one of the last days of the research season. The bird is trapped at a banding station. During this process, a traditional falconry hood is put over the bird's head to keep it calm. The device itself is harnessed onto the bird, mimicking the idea of wearing a backpack. The harness is sewn together with dental floss, of all things, because that will decay after about a year, the expected lifetime of the device.

Once the device is secure and we've ensured that it is safe, the bird is released. Each of the GSM-birds gets a name to make it easier to keep track of each of them. The first GSM-bird was named Augusta, and each subsequent birds has had a name starting with the next letter of the alphabet. This hawk was the J-bird, and so the banders named her "Juanita."

After the bird is released, it is a waiting game. And eventually, we started to receive GPS-coordinates from Juanita's device. Juanita flew south from the Marin Headlands, and after only a couple of days, settled into a neighborhood, where she remained for the following month. This map shows the positions of all of the GSM-birds that have reported. Juanita is pink.

Here is a zoomed in version. There's clearly plenty of prey to eat and nice trees to perch on in this neighborhood.

The map can be seen here: http://www.parksconservancy.org/conservation/plants-animals/raptors/research/gsm-tracking.html

So far, eight birds have provided us with interested data-points, all of them red-tailed hawks. And the lesson so far, which further confirms what previous studies of raptor migration have shown, is that there is no rhyme or reason to red-tailed hawk migration in the West coast. It seems that they go where it is most convenient for them to go.