Santa Rosa Island Raptor banding 2015

Anna FasoliBanding, Field Work, Science1 Comment

I’ve been working on Santa Rosa Island for the Institute for Wildlife Studies for nearly four months now, monitoring Peregrine Falcon and Bald Eagle nests. This week was banding week on SRI, the culmination of all of our hours of observation and hiking. I have lots of photos from the last few months and posts to write, but I figured I’d jump to this week since it ranks as one of my best weeks of field work! (Right up there with the night of banding 48 Northern Saw-wet Owls in western PA, the night I was stalked by multiple angry moose in Idaho while doing Flammulated Owl surveys, and the best day of hawkwatching ever in Belize).

Our peregrines had much success this season; only the Lime Point pair had a known failed nest before hatching, and just one pair, Trancion, had larger chicks “disappear” with no explanation between this tour and last tour. The Water Canyon pair never seemed to get their act together, and despite copulating many times, never incubated eggs long enough for us to find them.

The Trap Canyon Bald Eagle nest failed, but did incubate either to near full term or young unseen chicks. The Lopez pair successfully raised one chick; most of the season, we often thought we saw a second in the nest, but were too far to tell for sure. Former breeding male #39 has been replaced by breeding male #69, who is now paired with female #43 here. We banded their male chick and he was wing-tagged as #50, so be sure to follow his travels in the future! There are two other “pairs” of eagles that seem to like SRI, in addition to a few younger individuals, so hopefully next year we will see another solid territory form, if not two! Follow the Bald Eagle sagas here on the IWS discussion forum.

Male #43 keeps a close eye on his chick - Lopez Territory, Santa Rosa Island

Female #43 keeps a close eye on her chick – Lopez Territory, Santa Rosa Island

#50, a small male Bald Eagle chick - Lopez territory, Santa Rosa Island

#50, a small male Bald Eagle chick – Lopez territory, Santa Rosa Island

By far the best part of any field season is banding week/month. Here on SRI, most of our Peregrines were on the same nesting schedule, and we were able to band most of them this week. You can confidently sex peregrine chicks at 18 days or older, and all but three of our active territories were at least this old.  Band recoveries and resights from the Channel Island Peregrine Falcon population gives IWS valuable insight into the life history and general patterns of dispersal of juveniles, aiding in current and future conservation efforts and population monitoring.  Keep in mind you should never approach a raptor nest for ANY reason. The USFWS clearly defines illegal behavior disturbing raptors in both the Migratory Bird Treaty Act, and the Bald Eagle Protection Act. In the latter, the focus is on Eagles, but disturbance towards other raptors is covered in the 1970 amendment to the act incorporating other raptors. The Migratory Bird Treaty Act makes it illegal to take (kill, wound, pursue, shoot, shoot at, poison, capture, trap, collect, molest or disturb) birds of prey. Disturb is defined in the Eagle Act as “to agitate or bother a bald or golden eagles, or nesting birds-of-prey, to a degree that caused, or is likely to cause, based on the best scientific information available, 1) injury to an eagle,2) a decrease in its productivity, by substantially interfering with normal breeding, feeding, or sheltering behavior, or 3) nest abandonment, by substantially interfering with normal breeding, feeding, or sheltering behavior.”

Banding Peregrine Falcon chicks is easier said than done.  Our boss, Dr. Pete Sharpe, has had much experience accessing eyries from precarious locations, so the operation runs very smoothly. Once above an eyrie, Pete would set up shop with his climbing gear, and one of us would observe from a distance to assess the status of chicks in the eyrie and guide Pete to the right spot. Someone would also be above to make sure Pete’s setup was solid.  Meanwhile, female Peregrines would take passes at all of us, doing her best to intimidate us. The male peregrines sometimes joined in, but typically watched from afar. Adults usually settled down once Pete was off the cliff face.

Pete approaches the single Gnoma chick, our older chick on the island at 27 days

Pete approaches the single Gnoma chick, our oldest chick on the island at 27 days

 

Absolutely nothing happens at an eyrie without the female knowing about it.

Absolutely nothing happens at an eyrie without the female knowing about it.

Orrs Camp peregrine on the scene

Orrs Camp peregrine on the scene

Peregrine Falcon - female, Gnoma Territory, Santa Rosa Island

Peregrine Falcon – female, Gnoma Territory, Santa Rosa Island

Carrington peregrine in a stoop - Santa Rosa Island

Carrington peregrine in a stoop – Santa Rosa Island

Peregrine Falcon - female, Bonn Point Territory, Santa Rosa Island

Peregrine Falcon – female, Bonn Point Territory, Santa Rosa Island

Meanwhile, the chicks quietly lay motionless in the eyrie, with absolutely no clue as to what was going on in the world. Minutes later, Pete would simply transfer them into a handling bag, and bring them to solid ground for banding. Putting them back was just as harmless, and chicks always quickly settle right back into their cozy lairs.  The banding process is pretty quick and painless and took just a few minutes per chick. In total we banded 9 peregrine chicks from five territories, in addition to the Lopez Bald Eagle chick.

By far my favorite banding day was our expedition to the Carrington eyrie. This eyrie remained a mystery most of the season due to fog and very distant observation point. Late in the season on a clear weather day I was finally able to see an adult take food into a small lair, nearly at the top of the ridge line, much higher than the previous year’s eyrie. The location is an impressive cliff face high above the ocean, used by Pelagic and Brandt’s Cormorants, among other species, for nesting. It is truly an awe-inspiring place. Of course on banding day, gale-force winds made for a dramatic experience. While Pete descended to the eyrie with his climbing rope, I approached it on foot for photographs from a side angle.

Pete descends to the Carrington eyrie

Pete descends to the Carrington eyrie

What awaited me on this ledge was really one of the most amazing things I’ve seen in my 10 years of field work; three tiny peregrine chicks laying on a tiny ledge, hundreds of feet above a raging ocean, pelicans, cormorants, and ravens blowing by, and winds gusting over 35 miles per hour, if not more.

Carrington eyrie

Need a little perspective in life? Carrington eyrie, Santa Rosa Island

A unique perspective into a peregrine eyrie at Carrington

A unique perspective into a peregrine eyrie at Carrington

In the eyrie of the Carrington chicks

In the eyrie of the Carrington chicks

While at first glance the chicks looked helpless and even oblivious on such a dramatic landscape, they exuded a true confidence in their existence as a species that thrives in such an extreme habitat, just by the simple act of being able to survive their first 20 days of life in such a situation. I felt more helpless and vulnerable than they ever would, perched precariously over the same landscape where one false move can be your last mistake. This eyrie is a perfect example of the harsh conditions that the Channel Island Peregrines are perfectly adapted to living in. After banding, the chicks settled back in like we were never there.

Peregrine Falcon chicks can be accurately aged by measuring the length of the emerging feathers from their sheaths

Peregrine Falcon chicks can be accurately aged by measuring the length of the emerging tail feathers from their sheaths

Peregrine Falcon chick from Carrington eyrie, about 20 days old - Santa Rosa Island

Peregrine Falcon chick from Carrington eyrie, about 20 days old – Santa Rosa Island

Next tour will be our last on Santa Rosa, and we will check on all the chicks one last time. Thanks to Dr. Sharpe and IWS, IWS supporters, and all of the National Park Staff for such an amazing experience in such a unique location; this field season will be a hard one to top.

 

  • Steve Brenner

    This is wicked awesome! Raptor nestlings are so kick-ass