Thursday, October 25, 2012

Many More Migrants!!!

Since the Farallonathon, we have been quite busy counting and banding good numbers of migrant birds. On Oct 5th, this juvenile tundrius Peregrine Falcon rested briefly on the island before continuing south.

On the 7th, we captured an apparently pure Yellow-shafted Flicker female and at the same time a male Flicker Intergrade.  On the Farallones, pure Yellow-shafted Flickers are a bit rarer than intergrades, but usually average about one a year.  Note how the intergrade on the left has a bit of orange on the underwings, a red and black malar mark, and blue and brown on the face.  The yellow-shafted has pure yellow underwings and an entirely brown face and throat.

This same day we captured a juvenile male Black-throated Blue Warbler, which was still present the following day.  Check out those pointed rects (AKA, tail feathers)!

Also present on the 8th was a female Varied Thrush.

And the Red-breasted Nuthatch invasion continued strong until about the 20th of October. On the 12th, we banded and tallied 53 of these nasal honkers.

On the 10th, we found our 2nd Black-and-white Warbler of the fall creeping about on the rocks with the nuthatches.

A nicely overcast day on the 11th and 12th brought lots of new birds, dominated mostly by a huge influx of Red-breasted Nuthatches and Ruby-crowned Kinglets.  The vegetation around the mistnets was swarming with these guys and kept us all very busy.  On the 11th we estimated there were at least 40 of these kinglets, and on the 12th, our estimate was 78!

The highlights of the day, though, were the island's 3rd record of Yellow-bellied Sapsucker and 6th record of Evening Grosbeak!  Both birds were first seen at the lighthouse.  The sapsucker was not seen elsewhere, but the grosbeak eventually flew into our mistnet.  Luckily, a camera was handy at the lighthouse to document these birds as soon as they landed because you never know if they will be seen again.  For the sapsucker, there was a bit of indecision at first as to whether it was a Yellow-bellied or Red-naped, because, despite the lack of red on the nape, we were uncertain as to whether a juvenile Yellow-bellied could begin its pre-formative molt this early.  Thankfully, several sapsucker experts viewed the photos and concurred that it was a probably a pure Yellow-bellied.  Furthermore, an article by Mlodinow et al. (Birding, 2006), pointed out that nearly all Red-naped Sapsuckers have a red nape by October 1st.

The Evening Grosbeak was an adult male!

We also found our first Purple Finches of the season.  Here's an adult male that was present with 4 streaky birds that were either females or immature males.

In addition to birds, we caught our 2nd Hoary Bat of the season!

On the 12th, we did not find any mega-rarities, but it was the biggest day of the fall, with at least 617 landbirds recorded on the island.  High counts for the year were recorded for Violet-green Swallow (125), Red-breasted Nuthatch (53), Ruby-crowned Kinglet (78), Myrtle Warbler (29), White-crowned Sparrow (48), Golden-crowned Sparrow (85), and Oregon Junco (52).

Here's a juvenile Violet-green Swallow in heavy molt.  Check out the molt-limits in the wings!

One noteworthy bird found this day was a Sabine's Gull that was plucked off the water by a Peregrine Falcon.  Unfortunately, the only person who got to see the gull was the person shooting the photos.  This was only our second Sabine's Gull of the year. 

Also nice to see was a late Ash-throated Flycatcher.

And our first Swamp Sparrow of the year was bopping about our yard:

On the 13th, the clouds broke and the winds started blowing out of the northwest, but we continued to get good numbers of birds and even a couple rarities showed up.  During the morning pelican survey, we spotted an adult Brown Booby perched on Sugarloaf Islet.  Apparently, this bird was seen the previous day at Pt. Reyes. The last person to see it said it was heading southwest, "perhaps in the direction of the Farallon Islands."   Nice guess!  With the gannet on Sugarloaf too, we had a two Sulid day!  How many times has that happened in California?

Later in the afternoon, we found our 2nd Black-throated Green Warbler of the fall, only this time it was found in a mistnet, so its identity was greatly simplified and photographing it was a cinch.

We also had two more White-tailed Kites show up, which makes 13 and 14 for the year.  From 1967 (when PRBO started surveys on the Farallones) to 2000, there had only been 23 kite sightings.  From 2000 to 2011, we have seen 36.  What could be causing this increase?  Is kite habitat improving on the mainland?  It seems unlikely since they require open grasslands (preferably ungrazed) for foraging; golf courses, vineyards, and housing developments destroy kite habitat. It would be interesting to know if the autumn hawkwatch at the Golden Gate Raptor Observatory is also seeing more kites.  Anyway, this bird can be identified as a juvenile by the rusty feathers still present on its underparts.

The 14th to the 16th saw many landbirds depart.  A few lingering birds provided nice photos.  Western Meadowlarks usually arrive during October and many can hang around to over-winter.

This Chestnut-sided Warbler first arrived on the 6th and put on a gram of fat in a week.  It was last seen on the 19th.

On the 17th, the weather began to improve and several more arrivals found the island.  Brown Creepers are uncommon fall migrants on the island.

An Ovenbird was also a nice find.

This Barn Owl has been lingering around on the island all fall.  It has been shifting its roost every few days, so we don't always find it.

The 18th ended up being a pretty nice day.  This snipe had quite a bit of white on the trailing edge of the wing.  This could be a Common Snipe from Eurasia, but without a photo of the underwing, we'll never know.

Late in the day, this juvenile Brown Booby rode up to the island on a fishing boat.  While it was approaching, we thought it might be a Red-footed Booby.  The sharply cut hood across the breast and the white mottling on the underwings clearly identified this bird as a Brown Booby.  Three species of Sulid in one day on the Farallones will have to happen some other day.

Late in the day, a Harris's Sparrow was found flocking with a couple juncos on the outskirts of our survey area.  Just before sunset, a Grasshopper Sparrow was found at this same location from somebody looking for the Harris's Sparrow.

Lastly, on the 19th, the longspur that had been poorly seen the previous two days was photographed and identified as a Lapland.

The weather turned ugly on the 20th with howling northwest winds that blew all day on the 21st too.  Although this weather and the storm that followed weren't good for bringing landbirds to the island, we finally started seeing Buller's Shearwaters, with 300 counted on the 20th and 240 on the 22nd.  Fulmars have also increased, and we are seeing good numbers of Black-vented Shearwaters.  Hopefully the landbird migration will increase again once the weather settles back down.

Saturday, October 13, 2012

Farallonathon Results

With a promising weather forecast calling for light south winds, we eagerly anticipated the final two days of our Farallonathon - a week-long fundraiser that helps fund our study of the island's wildlife.

DAY 6 - The winds were perfectly southeast and light, but the visibility was too far, so the great landbird wave must have flown back to the mainland.  Still we managed to find a few new points.  A far from home House Wren was a nice addition to our list.  Although we normally see a few of these earlier during August and September, this was our first for the year.

One wave that did materialize was a Burrowing Owl wave.  While conducting our morning surveys, owls were flushing from everywhere.  It took quite an effort to avoid flushing them and to keep track of the ones we did flush.  By the end of the day, our Burrowing Owl intern, Maggie Spilatro, had tallied a very impressive island high count of 17.  Furthermore, the previous island high count of 11 was aided by telemetry, which obviously makes finding the owls much easier.  Here's one of the owls roosting in its preferred Farallon habitat - a rocky crevice.

Even though we saw Rock Wren on the first day of our Farallonathon, we were pretty excited to finally capture one.  Considering that most of this island we live on is rock, there is no habitat to concentrate them near our nets like the other birds, so capturing one is a very low probability event.  This bird was aged as a juvenile by its incompletely ossified skull and the molt limit that was present in its wing.

In addition to the point for the House Wren, we also found our first Western Sandpiper, Brewer's Sparrow, and White-throated Sparrows.  At the end of the day, another point showed up when a Greater White-fronted Goose took brief refuge on the island. This juvenile lacks the white around its bill that gave its species their name.

At around the same time that we found the goose, we also spotted a shark attack in Mirounga Bay to boost our daily total by an extra 5 points.  The five new migrant birds and the shark attack brought our 6-day total up to 150.

DAY 7 - With just 3 knots of wind out of the southeast and 10 miles of visibility, we really thought our final Farallonathon day had the potential to be epic.  Inexplicably, though, the wave did not materialize.  Instead, we just picked up a few new arrivals, albeit a few extra-stellar arrivals.  While conducting shark watch in the morning, Dan Maxwell spotted a nice Hermit Warbler bopping around on the rocks at the lighthouse.

He then got a fleeting glimpse of a bird that appeared similar, but even brighter.  Over our handheld radios, he announced that he might have seen a Black-throated Green Warbler.  After several hours of anguished searching, Maggie Spilatro relocated the bird on Pointy Cliff while searching for roosting Burrowing Owls.  This time Dan got excellent photos for undeniable proof of his sighting.  This is a species we normally only see once every other year.

Even more exciting than the pretty warblers was when Dan pulled a drab, olive-colored thrush out of the PRBO house net that he had never seen before; a thrush that few people have ever seen in California.  The Farallon Islands, though, is the ideal place to find a reclusive species such as this, where the sparse vegetation concentrates skulkers around the island's four trees.  In fact, 12 of the previous 22 records in California have come from this local, including the state's first record on 3 October 1970.  Separating this species from other Catharus thrushes is fairly straightforward when one is seen well.  To differentiate this bird from the similar olive-backed Swainson's Thrush, note how its face is washed with gray and that it lacks the buffy spectacled appearance of a Swainson's Thrush.  Veeries from western Canada can be fairly dark as well, but they should still show more rufous to the upperparts, whiter flanks, and small, indistinct spots on the chest.  Because Gray-cheeked Thrushes are seen so infrequently in California, all records of this species need to be reviewed by the California Bird Records Committee to determine whether the sighting was supported with sufficient evidence rule out other similar species.

In addition to these birds, we found a distant Flesh-footed Shearwater, a Killdeer, and a flyby Cliff Swallow.  Thankfully we also saw two shark attacks (each worth 5 points) and a shark breaching out of the water (worth 1 point).  With the 5 points for the CBRC-worthy Gray-cheeked Thrush and 5 points for the other new migrant birds, we were sitting at the end of dinner with 171 points - a respectable finish.  But there was still one more animal that we had searched for a few nights previous without success.  With just 28 minutes remaining before midnight, and the end of Farallonathon, we succeeded in finding a juvenile Arboreal Salamander crawling around on the rocks to bring our total up to 172.

So how did our 21st Farallonathon rank against our previous attempts?  Using our current scoring system, 172 points is just 3 points below the average of 175.29.  Still we found some pretty exciting birds such as the Arctic Warbler and the Gray-cheeked Thrush, and we got to see six shark attacks!  While the Farallonathon is a lot of fun for us, the main reason we do it is to raise money so we can continue our research.  If you enjoy reading about the wildlife we study and would like to help us conserve the Farallon ecosystem, please visit the following website and make a donation:

Thanks for following this year's Farallon-a-thon and see you next year!

Wednesday, October 03, 2012

The Farallonathon has Begun

On Sept 28th, we started our annual fundraiser that we call the Farallonathon!  Initiated in 1992, the Farallonathon was created to recognize the truly unique elements of the Farallones, while at the same time participating in PRBO’s Annual Bird-A-Thon.  The Farallonathon consists of a one week bio-blitz where we identify as many species of wildlife as possible. Instead of counting just species of birds on a single day, we count all of the animals we encounter including birds, fish, marine mammals, insects, and any other wildlife we find over an entire week.  We even assign points for rare and interesting wildlife events such as shark attacks and birds never before seen on the Farallones.

DAY 1 - We started out with light southeast winds, but dense fog limited visibility to just 1/4 mile. This meant that few birds would be able to find the island. However, we quickly spotted the Northern Gannet that was first found on April 25th. Since this was a first record for the Pacific Ocean, it was also a first island record, which means that it was worth ten points.

Thankfully, the fog lifted by 10 am, and the migrants that were flying around began to descend upon the island. We were immediately inundated in the banding lab with Red-breasted Nuthatches. Apparently their food supply crashed on their breeding grounds, and they are irrupting southward in huge numbers in search of food. On this day, we estimated a total of 54 individuals on the island, with 42 birds banded. This photo is of a nuthatch perched on the lichen-encrusted wall of the lighthouse. With high enough magnification, it is possible for us to see the microscopic insects that crawl over the walls. With their proportionately large eyes (compared to humans), the nuthatches and other birds are able to see and take advantage of this abundant food source

A huge surprise, though, was an Arctic Warbler that we found in the Coast Guard House mistnet. This is a species that breeds in the boreal forests of northeastern Europe, Asia, and Alaska. They mostly winter in southeast Asia, so they are extremely rare in North America outside of Alaska. In fact, prior to this bird, there were only eight records, 1 in Baja California and 7 in Alta California, which includes one previous record from the Farallones in 2005. Because this is a CBRC bird, we received five points for this wayward vagrant. The relatively short wing and bill, along with the yellow wash to the underparts and greenish upperparts, indicate that this was probably of the Alaskan subspecies, kennicotti.

Besides the two mega-vagrants (Arctic Warbler and Northern Gannet), we also found a mega rare bird for the island, a Ruddy Duck. Nearly all ducks are rare at the Farallones, with the exception of Northern Pintail and Surf Scoter, but it has been well over a decade since a Ruddy Duck was last seen on the island. The white cheek indicates that this is a male. In  eclipse plumage, males attain a drab appearance such as this duck, but in breeding plumage they have a bright rufous body; this bird had one rufous feather on its right side.

Several other species arrived this day as well including a Western Palm Warbler, a Chestnut-sided Warbler, and 8 Vaux's Swifts.

We also saw all 5 species of normally occurring pinnipeds on the island: Harbor Seal, Northern Elephant Seal, Northern Fur Seal, Steller Sea Lion, and California Sea Lion.  This Harbor Seal was swimming just off shore.

We also add Farallonathon points for butterflies and dragonflies.  Most of the species we see on the Farallones are highly migratory.  Variegated Meadowhawks, such as the one below, frequently make the over-water crossing to the island.

We finished this first day with a total of 96 points: 9 for the breeding birds (Black Oystercatcher, Western Gull, Pelagic Cormorant, Brandt's Cormorant, Common Murre, Pigeon Guillemot, Rhinoceros Auklet, Cassin's Auklet, Tufted Puffin); 61 for normal migrant birds; 5 for pinnipeds; 2 for cetaceans (1 for the resident gray whales and another for a Humpback Whale off Fisherman's Bay); 1 for a butterfly (Red Admiral); 3 for dragonflies (Green Darner, Black Saddlebags, and Variegated Meadowhawk); 5 for a species that needs to be reviewed by the California Bird Records Committee (Arctic Warbler); and 10 for a first island record (Northern Gannet).

DAY 2 - The winds in the morning were still light, but the fog was thicker and dropped our visibility to just a few miles for the entire day.  Still we managed to find 2 new butterflies (West Coast Lady and Painted Lady), and 15 new migrant bird species including a female Black-throated Blue Warbler,  a Magnolia Warbler, an Ovenbird, and a Tennessee Warbler. This increased our Farallonathon total to 113.

DAY 3 - Dense fog continued this morning, dropping visibility to just 1/8 of a mile.  Around noon, a strong northwest wind blew away the fog, and visibility increased to 30 miles, so we could easily see the San Francisco Peninsula.  Neither of these developments boded well for migrant birds to arrive on the island, as the strong northwest winds aided the birds that were over the ocean back to the mainland.  Although we could not find a single new Farallonathon point, we were able to get Peter Pyle, the founder of the Farallonathon, three new species for his Faralist.  He was on a pelagic trip with Shearwater Journeys, and we were able to get him on the Eurasian Collared-Doves, the Ruddy Duck, and the Northern Gannet.  His island list increased to 363, but our Farallonathon total remained at 113.

DAY 4 - More strong winds out of the north and northwest and high visibility (we could see Mt Diablo 60 miles away) meant that we would not see many new migrants.  With the morning winds coming off of Point Reyes, though, and news of big flights of Broad-winged Hawks in Marin, we were hoping that this species would cross the ocean and provide a first island record.  Unfortunately, this did not happen, but two White-tailed Kites did brave the crossing, and we saw them pass to our east.  Three other species of migrant birds were also new: Pacific Wren, Swainson's Thrush, and Spotted Towhee. We also found our second bat of the fall hanging in one of our three Monterey Cypresses.  We also added a point for the Farallon Cave Cricket, the only endemic species on the island. The only good news to the increased visibility was that we were able to spot a shark attack in Mirounga Bay, which is worth five points.  These points increased our total to 124.

DAY 5 - The northwest winds and high visibility continued to plague our Farallonathon, and we were only able to add 2 more migrant birds, a pair of European Starlings and a "heard only" Black-bellied Plover.  An Ashy Storm-Petrel survey revealed several active nests for another point.  Although the great visibility ruined our chances for a migrant bird wave, we were able to find a pod of 50 Short-beaked Common Dolphins swimming past the island.  Luckily they didn't come too close to the island as the sharks were busy in the afternoon, with two attacks in Mirounga Bay off Saddle Rock.  The first involved three sharks and lasted for nearly 30 minutes.  The second was closer to shore and ended fairly quickly.  The two attacks added 10 points and the two additional sharks at the attack added two more to increase our overall total to 140.

With only two more days to go, we'll need some good weather to come close to the record.  The forecast looks promising, with south winds and an increasing marine layer.  So long as we don't get fog, we may get a good wave.

So, what’s a typical ‘score’ for a Farallonathon?  During the last 20 years, scores have ranged from a low of 129 points to a high of 240 (a good year for shark attacks)!  The very first Farallonathon began auspiciously with a mega-rare Asian vagrant, the Northern Wheatear, but ended with only a modest 152 points due to very few shark attacks. 

Please consider supporting our research by pledging either a per-point amount or a flat donation for the event.  Money raised from this event goes directly to supporting Farallon research allowing us to purchase biological equipment, food and supplies for island personnel, and pay PRBO staff to analyze and publish the data we collect.  The information gathered from our research helps us and others protect the wildlife that use these unique islands and the marine environment that surrounds them.

To donate a flat amount online, simply go to the Farallonathon team webpage: and donate online. If you prefer to make a donation based on our point system or do not want to use the online method, please email Jim Tietz (,  Pete Warzybok (, or Russ Bradley (  Your participation allows us to continue studying this unique and vital ecosystem on the California Coast.

Thank you,
Jim Tietz
PRBO Farallon Biologist