Sunday, November 03, 2013

The Faces of Fall

The beginning of November brings an end to another year of monitoring autumn bird migration in southwest Idaho. After my brief trip to Spain to study bird migration there (see previous blog posts), I returned to Idaho to take my spot in a plywood box on the mountain, attempting to lure in raptors for banding, measuring, and release. The Idaho Bird Observatory operates two banding stations, one at Lucky Peak and one at Boise Peak, and I split my time between the two.

I trapped raptors three days a week from early September through the middle of October. On my watch, we banded 165 migrants in 18 days (not all trapped and banded by me as I often had an assistant with me – Thank you Jordan, Michelle, Teague and David). For me the season started off with the usual suspects (American Kestrel, Sharp-shinned Hawk, Cooper’s Hawk, and an occasional juvenile Red-tailed Hawk), but I finished with some spectacular diversity. I have included photos of some of the highlights.

The Idaho Bird Observatory has been banding birds on the Boise Ridge for 20 years. The data we gather has been used to advance our scientific understanding of these species and to inform management and conservation plans by various government agencies. The data has been used in a number of scientific publications, two of which I have authored.

This work is performed by trained biologists with special permits from the US government, the state of Idaho, permission from the local Idaho Department of Fish and Game, and authorization from the Boise State University Animal Care and Use Committee which helps to ensure that our impact on the animals is justified from a scientific perspective.

Second-year male Northern Goshawk (Accipiter gentilis) – Caught by David A.

To age raptors, we as banders use some unique and sometimes confusing terminology. A “Hatch-year” bird is in its first year. The bird was hatched in the spring. During autumn migration, the bird would be 5 or 6 months old. A “Second-year” bird is in its second year, or what we might usually call a 1 year old. During autumn migration these birds would be 17 or 18 months old. “After-hatch-year” indicates the bird could be a second-year or older, but we might not be able to tell. “After-second-year” means just that. The bird is at least a third year bird, at least 2 years old, or at least 29-30 months old. A Second-year bird is also a After-hatch-year, but Second-year is more precise if we can definitively conclude its age.

Each year at IBO we usually band 15 – 20 Northern Goshawks (out of 1000-1200 total raptors), but they are almost always Hatch-year birds. Last year we had one After-hatch-year. This year we banded three, all Second-year birds. The orange eye in the photo is indicative of a Second-year bird, but not conclusive. We used feather molt patterns to age this one; the bird still had some feathers that were juvenile.

Hatch-year Northern Goshawk (Accipiter gentilis)

The hatch-year feathers of a Northern Goshawk are brown instead of gray. During this birds second year it will molt its feathers to look like the second year bird above. Its eye will change from yellow to orange and eventually to red. Note, the eyes are blue when they are nestlings!

Hatch-year Northern Goshawk (Accipiter gentilis) talons.

For four years I have been trying to catch a Peregrine Falcon. I have been there when other have trapped them, but have not gotten one myself. That all changed this year.

Hatch-year female Peregrine Falcon (Falco peregrinus)

Among other indicators, the blue around the eye and cere indicate this is a hatch-year bird.

Hatch-year female Peregrine Falcon (Falco peregrinus)

I am particularly fond of Peregrine Falcons as they represent what humans can do with conservation if we are committed. The Peregrine Falcon was at risk of extinction. It was one of the motivators for the original passage of the endangered species act. We put the ESA into place and it worked. The Peregrine Falcon is no longer listed. We truly can make a difference for these species if we decide to.

For the past five years IBO has been in a drought when it comes to capturing Northern Harriers. That would change this year, and in a big way. We as a team trapped 12 harriers of all age and sex combinations. I trapped two.

After-second-year female Northern Harrier (Circus cyaneus)

Hatch-year female Northern Harrier (Circus cyaneus)

Note the eye color change. The female hatch-year birds have dark eyes, but the males do not. The Northern Harrier is very common in our area, we just don’t trap them often. In 20 years we have now trapped 74 harriers. In 1997 they trapped 13, in 1999 they trapped 9. The next highest count was 6.

In other rarely trapped birds, over the past 20 years the team has trapped only six Broad-winged Hawks. I had the honor of making that seven. The Broad-wing is very common in the east, but is rarely scene in Idaho. Our hawkwatch team (team that sits on the mountain and counts every migrating raptor they see) usually count on average 30 Broad-wings per year, although the number has been rising in recent years.

Hatch-year Broad-winged Hawk (Buteo platypterus)

Hatch-year Broad-winged Hawk (Buteo platypterus)

Hatch-year Red-tailed Hawk (Buteo jamaicensis)

Most of the Red-tailed Hawks we trap are hatch-year birds, but this year we had a surprising number of adults (3 or 4?).

After-second-year Red-tailed Hawk (Buteo jamaicensis) – caught by Jordan.

Merlins! We trap between 15 and 20 Merlins each year, but they are always a favorite. I ended up with 4 myself including the expected columbarius sub-species and one likely suckleyi sub-species.

Hatch-year Merlin (Falco columbarius)

Hatch-year Merlin (Falco columbarius)

The most abundance birds we band are the smaller Accipiter Hawks – Sharp-shinned Hawk and Cooper’s Hawk.

After-hatch-year Cooper Hawk (Accipiter cooperii)

After-second-year Sharp-shinned Hawk (Accipiter striatus)

I guess I didn’t take any picture of American Kestrels. They are our third most abundant bird and I banded a number this year.

We occasionally capture birds in the mist-net that are not raptors. Last year I had a Steller’s Jay and this year it was a Pileated Woodpecker.

Hatch-year female Pileated Woodpecker (Dryocopus pileatus)

That brings to a close my fall trapping season. It was a great, but rushed season. In a few weeks I will start a new job of winter banding resident American Kestrels for a population study.

Friday, November 01, 2013

The Non-avian Fauna of Tarifa

In September I completed a two week trip to Tarifa, Spain as a guest researcher from the Idaho Bird Observatory to study bird migration with Fundación Migres. You may read my previous reports on this trip -  Migration on an Unimaginable ScaleInto the Cage , and Studying the Smaller Avifauna of Tarifa.

The trip was a fantastic experience and very educational. I was in Tarifa for 14 days. While I “worked” every day, I did have opportunities to take in non-work activities as well. Here are some of the things I enjoyed while in Tarifa, beyond the birds.

The town of Tarifa. Tarifa is located on the southernmost tip of Spain, just 14 km from Africa. It is a fairly small town with a large tourist influence, but also a great deal of cultural significance, mostly the result of its locations.

Castillo de Tarifa (Castle of Tarifa)

The Castle of Tarifa was built in 960 ( The story implies that when the castle was under siege, the keeper of the castle, Alonso de Guzmán, refused to negotiate, even though the invaders had his son. When they threatened to kill his son, he sent them his knife (!

I never got the story of this structure, but I thought I was cool overlooking the harbor.

The Isle de Tarifa is an artificial island that was built out into the sea. The island is closed to the public, but you can walk out the causeway to the gates and look back at the town of Tarifa. In this picture I am facing north with the Atlantic ocean on the left and the Mediterranean Sea on the right. I did get to enter the island one morning when we performed seabird migration surveys.


Beatriz, Alejandro, and Nieves in old-town Tarifa.

The old part of Tarifa is made up of narrow cobblestone streets and is surrounded by a 13th century wall. Of course, all of the shops are fairly modern. We would often eat dinner in the newer part of town (less expensive, less crowded) and then walk into the old part of town for coffee or drinks. My hotel was only about a 5 minute walk away from the old part of town.

Whale watching. After monitoring the seabird migration one morning, Alejandro arranged for us to go out in search of Orcas on a whale watching trip. We had watched dolphins that morning from the shore, but this promised to be much, much closer. A week earlier, a friend of ours, Pablo, took excellent photos of Orca on this same trip.

The Orca are in a fairly predictable location. Tuna migrate each fall out of the Mediterranean and into the Atlantic. The Orca have learned this as have many fishermen. On the boat ride out, we had no doubts as to where the Orca and Tuna were, just look for the mass of boats.

Fishing boats and whale watching boats!

As we approached we could see whale spouts in the distance. Then, here they were! Right beside the boat!



We watched for 45 minutes as they appeared here and then over there. They move around so quickly that it is difficult to capture the action in photos. The big excitement came as one of the fishermen in a small boat caught a Tuna. The race was on. They were pulling in the Tuna, by hand! The Orca were swimming fast and hard to try and get there before they landed the fish. Unfortunately, or fortunately depending upon your perspective, the fishermen won the race. Here is the video.

It was clear that at least occasionally, the Orca win. It was a great day! Thanks to Alejandro and Turmares for the trip.

The food! The food in Spain was fantastic. The Migres team made sure I had the opportunity to experience a wide variety of dishes. For the most part, the food was much less expensive than here in the states. There were a few exceptions. Beatriz and I shared a plate of Paella down on the waterfront. This was fairly expensive, but no more so than it would be in the US. The dish is made to share and is delivered based on however many at the table order it. Here is a plate for two.

Paella with Beatriz!

For evening dinners we often ordered many half plates of food and served it “family-style”. It provided a great opportunity to try different foods. The tuna was always great, cuttlefish croquettes, squid prepared many different ways, pork, sea anemone, etc. Each meal starts with a shared plate of olives as an appetizer. I loved this aspect. In the U.S. we seemed to have lost the culture of food and shared meals. I enjoyed the aspect of group meals we shared as a team.

The most traditional local food of Tarifa would be the fish stew.

Cazuela de pescados y mariscos (I think…) Regardless, it was fantastic!

Post-meal coffee liquor.

Portabella, squid, chicken, tuna balls, potatoes, and beer = Awesome!

Los Alcornocales. On another day after work Alejandro took a group of us on a drive through Los Alcornocales National Park. This provided a great opportunity to see different habitats, stand eye-level with a Griffon Vulture in flight, taste local berries, learn about local plants, and hike into a waterfall.

Road through Los Alcornocales National Park

Strange berry. It wasn’t quite ripe.

Carnivorous plant!

The People! The best part of the trip were the people I met and worked with. The Migres team was very professional, great hosts, fun, and I consider them my close friends. I especially thank Alejandro and Beatriz my closest collaborators and primary hosts. I look forward to my continued collaboration with them and I hope to return to work with them again.

Alejandro with snake that was dropped by a Short-toed Eagle (a.k.a. snake eagle)

Nieves, Beatriz, Martina, Me.

Susana, Alejandro, Jordi (sp?), Carlos, Andres.

Alejandro, Pablo, Carlos (distant), Susana, Beatriz

I enjoyed the company of another friend in Spain that I didn’t happen to get any photos with. Eddie “the Eagle” is a retired Brit who would often join us at the count sites. I learned a great deal from him as well and enjoyed his company. I apologize to anyone else I left out.

What a fantastic trip! This concludes the summaries of my trip, but not my work with the Migres team. I am launching the analysis phase of our joint research project. I expect to submit a joint manuscript for publication some time this winter. Only time will tell if I am able to rejoin the team in Tarifa next fall.