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.

Thursday, October 31, 2013

Studying the Smaller Avifauna of Tarifa

I recently 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 Scale and Into the Cage.

Most of my time in Spain was spent counting migratory raptors and storks at the Strait of Gibraltar. However, when the weather interfered with raptor migration, or we had a unique opportunity, or in the evening after counting during the day, we did pursue some of the smaller species in the region. This included pursuing a songbird known among other names as a Rufous-tailed Scrub Robin and on another occasion, banding Barn Swallows.

The Rufous-tailed Scrub Robin is known by many English names including Rufous Scrub Robin, Rufous Bush Chat, Rufous Bush Robin and Rufous Warbler. They breed in Europe and migrate across the Strait of Gibraltar to Africa. The Migres team had a geolocator to attach to a breeding bird in Spain. Geolocators are very small electronic units which capture the length of each day for an entire year. The same bird must be recaptured a year later to extract the data. The birds are too small to carry a transmitter. Since these birds regularly return to the same breeding area year after year, recapturing them to extract the unit is a distinct possibility. We had reports that a bird was present on its breeding grounds just north of Tarifa two days in a row. Our job, after a day of banding Black Kites (Into the Cage) was to go north of Tarifa and trap a very specific bird.

Rufous-tailed Scrub Robin decoy to attract a territorial male.

We arrived at the reported location that evening. We set up a portable mist-net to capture the bird. We played a recording to attract the bird and deployed a decoy to bring it in close. Since we were on the breeding ground of this bird, and they are territorial, we would expect that any presence of a potential competitor would be met with a challenge from the resident bird. Then we waited. And waited.. And waited… The bird was not there. We likely missed it by one day! It was on its way to Africa, or more likely, it was already there. It would have been a life bird for me, but I did see a number of others while I was there including Little Owl, Eurasian Swift, and Common Swift.

Two days later, after a full day of counting migrating raptors at Cazalla, we headed north to Laguna de la Janda to band (or “ring” in European terms) Barn Swallows. La Janda is a fantastic place for birds. Even though we arrived just before dark, I was still able to tally up a quick eight new life birds including Kentish Plover, Collared Pratincole, European Turtle-Dove, Eurasian Reed-Warbler, Great Reed-Warbler, Zitting Cisticola, Western Yellow Wagtail, and the Spanish Sparrow! We were also graced with cool birds such as Flamingos, Ibis’, Black-shouldered Kites, Marsh Harrier, storks, Pied Avocets, etc.

The purpose of the Barn Swallow research is to explore the variability of feather molt of these birds during migration. It was once thought that they waited to molt feathers until they arrived on their winter grounds in Africa. Well, that does not appear to be true. Once again we set up a mist-net to capture the birds. We played a call, but this time it was a roosting call instead of a territorial call. The roosting call attracts flock oriented birds in to roost where they are trapped in the mist net. Since these birds are migrants, territorial calls would have no effect other than to possibly discourage birds from approaching the net. While we were still adjusting the equipment, we trapped a Eurasian Reed-Warbler and a Great Reed-Warbler in the net.

Great Reed-Warbler.

Susana, Pablo, and Alejandro banding Reed-Warblers.

Soon the sun would set and we would wait in the dark, and the bugs, lots of bugs, to go clear the net. When it was time we walked down to find 44 swallows in the net. Crash course in removing birds in the dark without a headlamp! In general, the swallows do not get as tangled as most songbirds and were quite easy to extract. We carried them back to begin the banding process. We set up an assembly line to process the birds. My job was to band, or ring, the birds. Susana kept me busy with a steady delivery of birds. Pablo measured the birds and Alejandro checked the molt patterns. Nieves recorded the data.

As I processed birds, I was swarmed by insects. In my eyes, ears, nose, you name it! It was brutal, but I had to stay focused on the birds. All went well until the last bird. I was expecting a 45th swallow, but it was a Eurasian Reed-Warbler. The swallows were calm and mellow in the hand and I got used their calm demeanor. As I pulled the Reed-Warbler out of the bag, it immediately escaped. I fumbled the last bird of the night! Regardless, it was a very successful evening.

We stopped for pizza on the way back, arriving at my hotel after 2 am. Not much sleep for the wicked.

Since my return in early September, I have been working hard banding migrating raptors in the states, completing two research manuscripts, and kicking off a joint manuscript project with my new friends from Spain. I will be providing updates on all of these projects in the coming weeks.

Saturday, September 14, 2013

Into the Cage–Banding Milano Negro in Spain

Welcome to my second post covering my recent trip to Tarifa Spain for the Idaho Bird Observatory to study avian migration with Fundación Migres. You can learn about the purpose of my trip by reading my first blog post titled Migration on an Unimaginable Scale.

On two occasions during my trip we banded Milano Negro (Black Kite - Milvus migrans). This highly migratory species travels from Europe down across the Strait of Gilbralter and into Africa for the non-breeding season. These birds rely on thermals which form over land due to the uneven warming of the earths surface. These rising columns of air, help the bird gain altitude before attempting the 10 mile crossing into Africa. Thermals do not form over water, so migrating birds must use powered flight to make the crossing. If the weather isn’t just right, they will wait in the fields near Tarifa for the weather to change. Each day hundreds more arrive and fill the fields. This is an excellent time to “band” (or “ring” if you are from Europe) these migrants as there are many present and there is little migration counting to be performed.

Milano Negro (Spanish) or Black Kite (English)

A large cage is first baited with bones and scraps from a local butcher shop. The Milanos are scavengers and are attracted to the “aged” meat. Hours usually pass before the first bird enters the cage. Once the first bird enters, it is not long before more show up. The numbers balloon quickly as hundred of birds show up, attracted by the action. The trigger is pulled and the birds are trapped. We captured 99 Milanos in one event, with hundreds more perched on the cage and on the ground around the cage.

99 Milanos in the cage.

Then came the very exciting and challenging job of extracting the birds from the cage. One may question the sanity of voluntarily walking into a cage with 99 free flying raptors. Body armor was not available! It’s a good thing the birds are fairly non-aggressive. If these were Red-tailed Hawks I would not have come out alive! The Milanos just droop their heads once they are picked up.

Juvenile Milano not putting up a fight.

The birds are placed into breathable bags and their legs tied to keep them secure. Once in the bags, the birds relax further and stay quite calm. The weather remained hostile for crossing the Strait so we weren’t delaying their journey and they should have gotten a good meal while in the cage.

Milanos ready for processing.

The birds are banded, measured and prepared for release. However, 19 lucky individuals were selected to help advance our scientific knowledge of migration by carrying a temporary backpack which contains a GPS unit and a cell phone text message component to transmit it location to the researcher on a regular basis.

GPS units with text messaging capability.

The researcher from Portugal is studying the flocking behavior of migratory birds. These GPS units will help him to determine to what degree these birds stick together. It will also help those of us studying migration at the Strait to understand the weather conditions under which they crossed, the time it took to cross, etc. It is tremendously valuable information.

GPS Backpack on a Milano.

The units are attached with harnesses which biodegrade under ultraviolet light. Within 3 months, the string will break, immediately releasing all four corners and freeing the bird of its obligation.

The experience exposed me to a new trapping technique used with scavenger birds, allowed me to practice the European measurements which are taken differently than in the US, and enabled me to spend time with the researchers discussing migration and flocking behavior. It was a fantastic experience.

Adult Milano ready to go to Africa!

Check back later for more information on my trip!

Thursday, September 05, 2013

Migration on an Unimaginable Scale

After leaving my 21 year career with Hewlett-Packard in 2009, I have spent my life in school getting two more degrees and one certificate (B.S. in Biology with an Emphasis in Ecology, M.S. in Raptor Biology, and a Graduate Certificate in Geospatial Information Analysis). During this time I have conducted research in two primary areas, publishing papers in both. The first area was the core theme of my graduate thesis, Northern Goshawk (Accipiter gentilis) Breeding Ecology. The second area is focused on avian migration. My work in this later area opened up a tremendous opportunity which I have just recently participated and is the topic of this post.

Most of my work is conducted as an employee and/or volunteer with the Idaho Bird Observatory (IBO). IBO is an "non-profit academic research and community outreach program of Boise State University focused on impacting human lives and contributing to conservation through a combination of research, education, and community engagement". My role is primarily in the research aspect of this mission, although I do also participate in outreach and education. I perform fieldwork, design projects, analyze data, and publish results. For some projects I am paid, for others I am not. Regardless, I love the birds and I love the work.

The IBO organization had received money from a grant to send students to Spain to study avian migration at the Strait of Gilbralter. I was lucky enough to be chosen for the trip. The last two weeks I have worked for Fundación Migres in southern Spain counting migrating raptors, banding Black Kites, banding Barn Swallows, and counting migrating seabirds. I met committed scientists, learned a tremendous amount, saw 47 new life birds, and enjoyed fabulous Spanish food and culture. It was a spectacular experience. This is the first of a series of posts highlighting my trip.

Cigüeña Blanca (White Stork - Ciconia ciconia) migrating to Africa.

The Strait of Gilbralter is one of three main sites where long-distance migrating raptors pass from Europe into Africa. Most of the birds in western Europe migrate down through Spain to the Strait where the crossing is only 14 km to Morocco. Some birds travel down Italy and island hop across the Mediterranean, while most eastern European birds travel through the middle east. Fundación Migres currently maintains two "count sites" for migrating raptors and storks near Tarifa for monitoring population trends, phenology changes, and the general ecology of migrating birds. I spent the majority of my time in Spain counting migrating birds at these two sites.

Map of the Strait Of Gilbralter. Count sites near Tarifa and near Algeciras.

Mount Sidi Moussa (Morocco) as viewed from Spain (14 km).

Each day one or two biologists are assigned to each count site to count all migrating raptors from 9:30am until 5:30pm. Each bird that is spotted must be identified and tracked to see if its flight direction is consistent with a migratory bird. With multiple mixed flocks in the sky at once, it can get fairly hectic. Of course, we do miss birds. There is no way to spot every one. We also likely count birds which don't end up crossing the strait. The point is to have a consistent effort and protocol so that the numbers we do collect can be a consistent index of the number of birds actually migrating. Since these site are excellent places to observe birds, many tourists also show up to watch the migration.

The work is both physically and mentally demanding. While there is a great deal of sitting involved, the strain on your neck (from looking up), on your arms (holding up binoculars), and on your eyes (staring through binoculars into bright sky) definitely takes its toll. It is mentally straining to stay focused for that length of time, often shuffling counts of up to 4 species at a time in your head. A single flock can contain hundreds or even thousands of birds (2300 White Storks was the biggest I saw). We used handheld counters to track counts of multiple species when things got busy.

Andres counting with 4 species counter.

Cazalla count site.

Algorrobo count site.

There are a number of challenges facing birds crossing the strait. It is not just the distance, the lack of thermals and wind make this a very challenging portion of their migration. Many raptors depend on thermals, or rising columns of air, to gain altitude. Thermals are generated by the uneven warming of air over land. They do not occur over water. Thus migrating raptors must use flapping power to maintain altitude when crossing water. This is easier for some raptors than others. Wind is the other challenge. A tail wind may help with the distance, but it also decreases the lift generated by a birds wing. A head wind, while enabling more lift, can decrease speed and thus increase the effort required. A strong east wind, a "Levante wind", can blow a bird off course into the open ocean. Unlike waterbirds, raptors are not able to land on water to rest, if they land, they die. The most challenging crossing conditions occur in a Levante wind, which unfortunately for the birds are common in autumn.

Abejero (Honey Buzzard - Pernis apivorus) uses natural flapping style of flight to easily cross the strait, even in difficult conditions.

Species which do not have a natural flapping style and are heavily dependent upon thermals, often must wait for the weather to improve before crossing. This can require days of waiting for the right conditions to cross. Each day, more and more migrants arrive in the fields around Tarifa waiting for the weather to change. Hundreds, even thousands of birds waiting. When the wind shifts, they leave en-masse. My first count day in Tarifa was one such day - 4400 Black Kites and 4300 White Storks made the crossing that day! Our count for the day? Over 9000 birds!

Milano Negro (Black Kite - Milvus migrans).

Black Kites "thermalling" up before crossing.

Cigüeña Blanca (White Stork - Ciconia ciconia) preparing to cross.

The spectacle of thousands of birds per day approaching the strait to cross is humbling. So much life, so much biomass, it seems inconceivable that this many animals exist. When the the Abejero (Honey Buzzard) started migrating we were counting over 3000 birds per day. The day after I left - over 20,000 Honey Buzzards! Unbelievable.

Alimoche (Egyptian Vulture - Neophron percnopterus).

Why study migration? Birds are a very important part of our natural and now human influenced ecosystems. A good portion of birds on the planet, over 40%, migrate on an annual basis. As the planet changes, so does the influence on individual bird species. A migratory bird faces new challenges in each stage of its annual life-cycle. Some are threatened on their breeding grounds, some on their wintering grounds, and nearly all on the journey in-between. Studying bird migration can provide early and relatively inexpensive insight into the trends within migratory species. This knowledge can better inform conservation measures before trends become too catastrophic.

Calzada - (Booted Eagle - Hieraaetus pennatus).

Fundación Migres now has a long-term dataset to investigate the trends in European long-distance migration. My role in all of this is to add to their published literature by creating a new research project analyzing their data and co-authoring a manuscript with them. We have chosen a preliminary topic and the work has begun. It should keep me busy through this fall. This is why I left my previous career - to spend time in the field, to analyze and publish results, and to positively impact the conservation of species on this planet. This is just the latest opportunity I have been given.

Culebrera (Short-toed Eagle - Circaetus gallicus).

The Fundación Migres team is a group of fantastic people. They are gracious hosts, they are incredibly knowledgeable, they taught me a great deal, and I now consider each one of them my friend. I hope I have the opportunity to return next year!

I will post more summaries in the coming days - Black Kite banding, Barn Swallow banding, seabird migration, and one on food and culture.