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.

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.

The Glamorous, Fabulous Ferruginous Hawk

(I'm no longer in California. I'll try to get my last few CA-themed blog posts written in the next couple of weeks before moving on to my next adventures!)

This is an article I wrote for the Golden Gate Parks Conservancy February 2014 e-ventures newsletter. It is currently published here:  http://www.parksconservancy.org/about/newsletters/park-e-ventures/2014/02-ggro.html

“Boy, I’d love to see a ferrug right now!”

This is one of the most often spoken statements by hawkwatchers at the Golden Gate Raptor Observatory, and understandably so. Large and majestic-looking, the Ferruginous Hawk (known as the “ferrug” in hawkwatcher short-hand) is arguably one of the most beautiful raptors we see at the GGRO. Adding to its desirability, Ferruginous Hawks are spotted from Hawk Hill no more than 20 times in a given year.

The Ferruginous Hawk is so named for the rusty-brown color infused on adults’ heads, backs, and upperwings. In the world of chemistry, rust is oxidized iron, known in the olden days as ferrous oxide. Add a couple letters and “ferrous” become “ferruginous.” The hawk’s scientific name also indicates its glamorous, physical appearance: Buteo regalis, which literally translates from Latin to mean “royal soaring-hawk.”

Often confused for an eagle because of its size, the Ferruginous Hawk is the largest North American buteo, the genus of hawks that includes Red-tailed Hawks, Red-shouldered Hawks, and Broad-winged Hawks. Identified by its characteristic long, tapered wings, large head, and robust chest, the Ferruginous Hawk is only one of three North American diurnal raptors to have legs feathered all the way to the toes (in addition to Rough-legged Hawks and Golden Eagles). In adults, these leg feathers are rusty-brown, forming a characteristic “V” shape that stands out when seen in flight. The chest of the Ferruginous Hawk is usually pale white, while the underwings of adults will have various amounts of rust-colored markings (brown in juveniles). 

Perhaps the most striking feature of these hawks, however, is the tail. In flight, the underside of the adult tail looks completely white, sometimes with light barring or some rust-color shining through towards the tip. Juveniles often show two to three gray bands towards the tip on the otherwise white tail.

During my first visit to Point Reyes National Seashore, I spent almost an hour watching a juvenile Ferruginous Hawk hunting over the grasslands. Using its long wings and tail to still in the air and moving its head back and forth, the hawk actively searched for jackrabbits and ground squirrels. Occasionally, it would stoop down and fly low over the ground before returning to its height to continue looking for prey. Cooperative hunting has also been reported in Ferruginous Hawks, where a male and female work together to catch prey.

For the motivated hawkwatchers, there are a few great places in the Bay Area to see Ferruginous Hawks overwintering. In Point Reyes, Pierce Point Road and the trail to Abbott’s Lagoon are surrounded by grassland habitat, ideal for seeing Ferruginous Hawks. Other areas worth checking out include Livermore Valley in Alameda County, Chileno Valley on the Marin-Sonoma County borderlands, and the southern extension of Chalome Valley between highway 41 and Bitterwater Road. The best time of year to look for Ferruginous Hawks in these areas is between December and February.

Seeing a Ferruginous Hawk from Hawk Hill is quite a treat. Although a sighting is rare, it is clear why hawkwatchers consistently consider this elusive bird to be truly glamorous!

(Thanks to Allen Fish, Bob Power, and Tim Behr for tips on where to find wintering Ferruginous Hawks!)

Road Trapping

Yesterday, I got a chance to experience "road trapping," which involves taking our raptor banding show on the road. Essentially, we drove around until we spotted a raptor. We chucked a trap out of the window of the car, waited for a few minutes to see if we could catch the bird, and then banded it right out of the trunk of the car.

Emma and Buzz band an American kestrel. All the banding materials are in the back of the car.

We spent the entire day driving around the Davis, CA, area. However, time flew by as we were constantly stopping and occasionally banding some incredible birds. Three of the six birds we banded yesterday were American kestrels, the charismatic little falcons that I have come to love this year.

Adult, female American kestrel.

Female American kestrels are aged by the final black bar on their tails. In this case, it was an adult bird because the last black bar is so much thicker than the other bars.

We were not successful in catching every bird we set the traps out for. Even so, just getting a chance to see some of these unique raptors was worth the trip.

An adult ferruginous hawk (the first adult I've ever seen). This bird is the definition of majestic.

Dark-morph adult red-tailed hawk.

The highlight of the day, however, was banding three adult red-shouldered hawks. There is a theory the other GGRO interns have developed that any black-and-white bird (especially if there is a hint of red) will automatically qualify as one of my favorites. Recent examples include pigeon guillemots, black phoebes, and California condors. Thus, these beautiful birds immediately won me over. So much so that I am writing in an uncharacteristically gushy way about them. But I'm putting science aside for this entry, because these birds are just plain amazing. See for yourself:

Red-shoulder #1.

Look at the black and the red and the white. Just look at it! Wow!

I demonstrate why this bird is called "red shouldered."

Are you seeing this bird? It's so cool!

Close-up of the feathers. Amazing.

Red-shoulder #2 was much redder on the body. Do you see this bird? Do you see how beautiful it is?

This is another shot of a red-shoulder looking incredible.

Red-shoulder #2 release shot.

This is red-shoulder #3, caught about 27.3 seconds after red-shoulder #2.

Some red-shoulders have particularly prominent hackles (feathers on the back of the skull), giving them a spiky-headed appearance.

So, here's the deal. I like birds (obviously). That being said, I like to think of myself as a scientist, biologist, what-have-you-ist. I like to take an objective perspective of my work and not resort to constant "ohhhhhhhh those birdies are soooooo cuuute!!" gushiness. That's not why I'm motivated to do what I do. However, I think it is important to take a step back every now and then and acknowledge the simple fact that these creatures are amazing, beautiful, incredible. Yesterday was an experience in research, but more importantly, in was an experience in awe-stricken appreciation.

Kiting

Ask most anyone to name some different families of raptors, and the list will usually include hawks, falcons, eagles, osprey, and sometimes even owls. It is rare, however, for someone to mention kites, at least in their first breath. The large, soaring buteos, the swift, agile falcons, and the majestic, charismatic eagles seem to be much more prevalent on our raptor-radars. It is a shame that kites are often absent from these lists, as they are unique and impressive raptors in their own right.

There are five species of kite that can be seen in North America. The one that has become familiar to me during my time in California is the white-tailed kite. Falcon-shaped with flight resembling that of a gull, the most prominent feature of this kite is probably its black shoulder patches. This inspired ornithologists to change the bird's name to "black-shouldered kite" during a brief identity crisis in the '80's.

An adult white-tailed kite is a striking sight to behold; in addition to the black shoulder patches, distinctive black carpal patches can be seen on the underside of the wing. The head, body, and tail are completely white, and the underwing becomes progressively dark moving closer to the tips of the primaries. The adult's eyes, surrounded by a patch of black, are a deep scarlet. Juveniles look similar, but with rufous-colored feathers along the breast, a narrow band towards the tip of the tail, and a brown-colored eye.

(photo: www.wikipedia.org/)

During a birding field trip to Skaggs Island yesterday, white-tailed kites were one of the most frequently spotted species of the day. Across the landscape, I spied multiple kites, perched in the bushes or displaying my favorite raptor behavior: kiting. In this hunting strategy, which just so happens to be the origin of their namesake, white-tailed kites hover in place over the landscape, flapping their wings in a way that is necessary to hold them and place and captivating for the hawkwatcher. The kites will continue to do this behavior until they see a rodent (which they prey on almost exclusively) and stoop down to strike or move on to investigate a different area.

When kiting, white-tailed kites look almost angelic in appearance.

Kite populations were declining rapidly at the start of the 20th century due to hunting and egg collection practices; white-tailed kites were all but extinct in California by 1940. However, thanks to protective legislation and the abundance of prey available to them at agricultural sites, their populations have rebounded since this time. Even so, there are rapid fluctuations in white-tailed kite population numbers from year to year due to similar fluctuations in prey availability. This makes it challenging to collect accurate censuses, and many ornithologists believe that we should still be watching white-tailed kites closely for signs of sudden, significant decline.

While white-tailed kites and all their kite cousins may not be the poster children of the raptor world, they are equally impressive and ecologically-essential. This is one bird I am going to miss seeing on a regular basis when I leave California and I believe it deserves equal time in the spotlight as its more-famous raptorial counterparts.

Banding 9/19: Hatch Year Female Cooper's Hawk

Particularly prominent "eyebrow"

This is a picture of me being yelled at by a Cooper's hawk.

Hawkwatch 9/18: Sun

It was a bright, sunny day on Hawk Hill today!

Another sunny day on Hawk Hill with temperatures in the 70's and a light wind coming from the west. We saw a lot of accipiters today, 28 Sharp-shinned Hawks and 41 Cooper's Hawks. To the great delight of the many hawkwatchers on the hill today (184 visitors on a Wednesday...maybe had something to do with the America's Cup final...), we also got some good looks at a Golden Eagle (subadult), a Ferruginous Hawk (juvenile), and two more Broad-winged Hawks. As usual, there were Red-tailed Hawks and Turkey Vulutres apleanty, and towards the end of the day, a Raven carrying a peanut-butter and jelly sandwhich was sighted as well.

Total Sightings: 235
Hours Counted: 5.5
HPH: 42.73
Total Species: 10

Golden Eagle silhouette.

Species Counts:
Turkey Vulture: 55
Sharp-shinned Hawk: 28
Cooper's Hawk: 41
Red-shouldered Hawk: 3
Broad-winged Hawk: 2
Red-tailed Hawk: 91
Ferruginous Hawk: 1
Golden Eagle: 1
American Kestrel: 3
Merlin: 1

Unidentified...
Accipiter: 8
Falcon: 1

Hawkwatch 9/17: Booby Watch

Oh, get your brain out of the gutter, please.

Birders get excited about seeing rare species, especially those that are keeping lists of birds seen in a certain state. For example, a blue-footed booby would be a big deal for birders listing California birds - this bird is rarely seen in California. So, when the hawkwatchers heard that a booby had been spotted at Land's End (the tip of San Francisco, easily seen from Hawk Hill) at 10:00 AM this morning, they started to get excited at the prospect of it potentially flying right past us. Thus, the south quadrant was given the extra task of "booby watch" today. (I giggled when given that assignment. Apparently, I refuse to grow up). Sadly, we never saw the bird.

Here's the HW report for the day:

Today was slow at the start, slow at the finish, with a flurry of raptor activity in the middle. The day was sunny and the wind direction was "all," seeming to change every three minutes or so. We were hopeful to get a look at the vagrant Blue-footed Booby, spotted just across the bay at 10AM today (thank you, eBird!) However, the raptors certainly kept our attention today. We got a good look at a juvenile Red-shouldered Hawk, followed by an even better look at its adult counterpart, a great lesson in distinguishing the two. Towards the end of the day, a distant dot was identified as a Ferruginous Hawk of unknown age. As for our usual suspects, the Turkey Vulutures beat out the Red-tailed Hawks by one bird today, 94-95.

An adult red-shouldered hawk (above) being ambushed by a juvenile Cooper's hawk (below).

The quintessential GGRO raptor: a juvenile red-tailed hawk.

Total Sightings: 251
Hours Counted: 5.5
HPH: 45.64
Total Species: 9

Species Counts:
Turkey Vulture: 95
Osprey: 2
Sharp-shinned Hawk: 13
Cooper's Hawk: 26
Red-shouldered Hawk: 4
Red-tailed Hawk: 94
Ferruginous Hawk: 1
American Kestrel: 5
Peregrine Falcon: 2

Unidentified...
Accipiter: 6
Buteo: 1
Falcon: 1
Raptor: 1

Banding 9/13: Small Sharpie

I went raptor banding again today and ended up banding two accipiters: a male Cooper's hawk and a female sharp-shinned hawk. As the migration picks up, these will be the two most common species we'll be banding, both because of the mass numbers of them that migrate through the Marin Headlands as well as the ease with which we are able to catch these particular species.

The sharp-shinned hawk is one of the smallest of the diurnal raptors in North America. It is funny to be banding them as they attempt to act "fierce" - biting at your finger for example - when in actuality, they just look really, really cute. The sharp-shinned hawk we banded today was a hatch-year female, and on the small side. For every bird we band, we have an "expected values chart" that lays out the average and mean range of all the measurements we take for a given species and sex. In this case, our female sharpie was on the low end of the mean range for all measurements.

Trying to look fierce. Actually looking cute.

Our data sheets and the "expected values chart."

Banding 9/12: Backpack

My backpack got locked into a fellow intern's car today, so I had to improv before heading up to the blind. Luckily, I found another pack in the lost and found and I was able to gather up some "lunch" including some granola bars, half a bag of peanut-butter pretzels, and some left-over banana walnut bread (lunch of champions!) At the end of the day, as I got into Lynn's car, I noticed that the window on the other side was rolled down - I could have gotten my backpack all along.

We banded one raptor this morning (the other blinds were much more productive today, including the first merlins of the season, an adult red-tailed hawk, a red-shouldered hawk, and a red-tailed hawk that got outfitted with a GSM tracking device). Our red-tail came out of nowhere without any warning. It was a hatch-year male. Since my initial taloning encounter, I've become much more confident handling and banding these big, sharp birds.

The rest of the day was pretty slow with very few birds passing by. We did see quite a bit of diversity, though, including an osprey, white-tailed kite, Northern harrier, and mysterious black falcon. By 3:00, the wind was blowing fast and we found ourselves surrounded by fog shortly thereafter.

Banded hatch-year red-tailed hawk.

This should probably be a meme.

Flying away!

Hawkwatch 9/11: Tweety Birds

It was a relatively slow day today demonstrated by our brief celebration at 3:00 when the count reached 100 raptors. Overcast with a light breeze, we mostly saw the usual: Red-tailed Hawks and Turkey Vultures (no Cooper's Hawks counted today!). There was some nice movement of non-raptor migrants ("tweety birds" as some hawkwatchers call them) to keep us occupied as well, including flocks of 23 White-throated Swifts, 20 Band-tailed Pigeons, and 15 Cedar Waxwings.

Anna let me play around with her fancy-DSLRey camera during the (great amounts of) downtime today. I took some picture of the non-migrant tweety birds that often hang out with us during the hawkwatch.

White-crowned sparrow.

Western scrub jay.

Total Sightings: 115

Hours Counted: 5.33
HPH: 21.58
Total Species: 6

Species Counts:
Turkey Vulture: 41
Northern Harrier: 2
Sharp-shinned Hawk: 1
Red-tailed Hawk: 65
American Kestrel: 4
Peregrine Falcon: 1

Unidentified...
Buteo: 1

Hawkwatch 9/9: Above the Fog, Away from the Fire

The Golden Gate Bridge, being consumed.

We found ourselves above a thick layer of fog on Hawk Hill today. From our vantage point, the sun was shining, and it looked to be a beautiful day of hawkwatching. My first bird of the day was a prairie falcon flying out of the North quadrant and across the landscape. Then, as the wind began to pick up, we started to count kettles of red-tailed hawks. They seemed tentative to cross over the thick fog in the bay, however, so they began to accumulate in the East. The challenge was to keep track of which red-tails had already been counted, which were joining the kettle, and which were flying away. This proved to be a tricky challenge. There was also an occassional peregrine falcon in the kettle, as well as the usual turkey vultures. By 2:00, the temperature had dropped significantly and we were surrounded by fog, so we ended the count early.

Approaching fog.

Our view by 2:00.

A couple other interesting sights of note:
-A group of five planes flew through the sky, writing some advertising message. However, their handwriting was terrible and we think they were advertising some sort of talent agency, but it was unclear. Maybe they need a talent agency to identify better sky-writers.

Successfactors?

-Yesterday afternoon, a fire started at Mt. Diablo, one of our distant landmarks. Throughout the day, we could see smoke billowing off of Mt. Diablo. At times, it looked like the fire was calming down and then, out of nowhere, a new, huge plume of smoke would appear. Pretty crazy to watch.

Distant wildfires.

Total Sightings: 152
Hours Counted: 4.25
HPH: 35.76
Total Species: 9

Species Counts:
Turkey Vulture: 21
Osprey: 1
Sharp-shinned Hawk: 4
Cooper's Hawk: 7
Broad-winged Hawk: 1
Red-tailed Hawk: 99
American Kestrel: 3
Peregrine Falcon: 4
Prairie Falcon: 1

Unidentified...
Accipiter: 3
Buteo: 2
Falcon: 2
Raptor: 4

Banding 9/7: Superstitious

Some of the volunteers in the GGRO banding program can be a little superstitious about the way things run in the banding blind. Yesterday, for example, as we got the blind set up for the day, I placed all of the banding tools out on the table in anticipation of the processing of a raptor. I was gently informed, however, that this could totally jinx our ability to catch a raptor in the first place. Sure enough, we spent the first three hours that morning staring at a birdless landscape.

Finally, my sight leader took it upon herself to put all the tools back in the drawer from whence they came. Five minutes later, we caught our first (and only) bird of the day, a male American kestrel.  I'm learning so much about science.

Male American kestrel.

Kestrels are one of the few raptors where males and females show distinctly different plumages. In this case, the male shows silvery/blue wings whereas the female is rusty with black stripes across the back and wings.

Male American kestrel tail: solid rusty color with a single, solid black stripe.

Female American kestrel tail: "tiger" striping all the way across. (We banded a female AMKE on Thursday - pretty cool to see both sexes up close within a couple days of each other).