Friday, November 25, 2011

A Farallon Thanksgiving

A common misconception about living on an island is that you undoubtedly eat poorly. No grocery store? Military rations it is! Fortunately, that is not the case here on the Southeast Farallon Islands. Every two weeks we are resupplied with food by a group of volunteers who do a large shop for us, picking up an assortment of fresh produce, dairy, meats and other goods we might need. So, despite what may have been envisioned for a SEFI thanksgiving, it is always a feast comparable to any mainland meal!

Liz prepping the stuffing:

 Mashed potatoes and blueberry-apple pie in the works:

 The turkey and a pie, almost ready:

Jim serving himself some stuffing and sweet potato casserole:

The meal:  stuffing, gravy, turkey, cranberry sauce, sweet potato casserole, mashed potatoes and sweet potato biscuits:

Blueberry-apple pie:

Chocolate pecan pie:

Tuesday, November 22, 2011

Spelunking for the Farallon Cave Cricket

In the early 1900’s, Milton Ray, a poet and scientist who visited the Farallones several times, described the Lost World Cave in the following poem:

                More strange the Lost World Cave. Ah me!
                How few have trod its rough dark floor,
                Where chambers weird in endless maze
                Far downward lead, through darksome ways.

Ray photographed the cave, but after his last visit, he stated that its entrance had been collapsed by islanders to prevent children from entering and getting lost.  Although, the reputed photograph of the Lost World Cave shows limestone features, which contradict the granitic composition of the island, contemporary islanders have always wondered about its existence and where it might be located.

Reproduced from "The Farallones, The Painted World, and Other Poems of California, vol. 2" by Milton Ray
On 11 and 12 November 2011, we explored all of the known, accessible Farallon caves with the crew of Island Conservation to estimate the population of the endemic Farallon Cave Cricket. The Farallon Islands are pockmarked with wave-carved sea caves.  Most of these caves are still at sea level, with waves rolling in and out, excavating minute quantities of material with each thundering slap.  Most of these caves, though, are difficult to access and unlikely to harbor crickets anyhow, so we did not enter them.  However, at some point in the island’s geologic past, the island was either uplifted 50 feet, or the sea level was 50 feet higher.  This left four caves that are deep enough for a cricket to evolve into a species found nowhere else on the planet.

The Farallon Cricket (Farallonophilus cavernicolus) was first described by David C. Rentz in 1972.  It is a member of the camel or cave cricket family (Rhaphidophoridae), which is quite diverse in California.  Species in this group are wingless and have a brownish, humpbacked appearance with large hindlegs and long antennae.  The Farallon Cave Cricket is no exception.  However, several anatomical features are sufficiently distinct from other members of the camel cricket family to warrant it a unique genus.  Behaviorally, the Farallon Cave Cricket frequently gathers together in small to large groups that can number up to 100 individuals.  When they feel threatened, as when a bright light is held up to them, they may drop off the cave wall or ceiling to the floor below.  They require moist areas and darkness. Little is known about their natural diet, but they will eat oats in captivity; it is thought that they may forage on organic material brought into the caves by nesting seabirds.

Farallon Cave Cricket.  November 12, 2011.
The first cave we explored was the Rabbit Cave, which is the largest known cave on the island and is located on the southeast facing slope of Lighthouse Hill.  This cave received its name from the rabbits that were introduced to the island in the 1800’s and used to plague islanders and wildlife alike.  After many failed attempts by previous islanders, PRBO biologists succeeded in eradicating the rabbits in 1975.  The entrance to this cave starts out as a 50 foot crawl before opening up into a spacious cavern that is nearly 20 feet high.  This open cavern extends back another 50 feet or so before petering out.  Although this is the largest cave on the island, the crickets were small (~ half an inch) and not especially numerous, with 700-800 present.  Perhaps this is due to the southeast orientation of the cave entrance that produces a relatively dry interior.

Spelunking crew exploring Rabbit Cave.
Dan Grout recording cricket data.
We then visited a small cave between E-seal Blind Hill and Pointy Cliff that has a 5 x 5 foot opening and extends back about 15 feet.  One islander recently got the creeps here, so this cave now goes by the name Spooky Cave.  This cave faces northwest so that the prevailing winds keep it moist and mossy.  Despite the cave's shallowness, there were approximately 300-500 crickets, a quarter of which were relatively large (nearly an inch long).

The approach to Spooky Cave.  Aren't you scared?
Spooky Cave's interior isn't too spooky
Corm Blind Cave was next on our spelunking tour.  This cave is only about 4 feet high and extends back about 12 feet.  It also faces northwest and is quite moist, but differs from the others in that it lacks a large, protective chamber behind a small opening that can shelter the crickets from the full force of the winds.  In this cave, we found about 100 crickets and a Burrowing Owl!

Corm Blind Hill Cave
On the northwest side of Shubrick Point is a large cave that we have recently named Cricket Cave.  The entrance is 6 x 9 feet, and the initial chamber is ~60 feet deep.  This chamber tapers down in the back and appears to end.  A narrow passage remains hidden until you walk right up to the end.  When we first discovered this passage last year, we wondered if we might have stumbled upon Lost World Cave.  The second chamber is impressive, and goes another 70 feet before tapering down again to a crawl space that apparently dead ends.  This is a much wetter cave than the others, with stalactites and many active formations.  There were 300-600 crickets within 25m of entrance, and even one in a spider web at the entrance itself.  There were ~500-700 crickets in the back chamber, at least 150 feet from entrance, and probably more than 1,000 crickets in total in this cave.

Dan Grout preparing to enter Cricket Cave
Cricket Cave's initial chamber narrowing down.
Interesting cave wall patterns
Cricket congregation showing different sizes
Nice stalactite formation 
Mushroom  stalactites growing off the walls
Although it seems the majority of Farallon Cave Crickets live in these large caves, they can also be found in smaller crevices.  During the night of November 18, while watching Cassin's Auklets and Arboreal Salamanders wander about, we saw ~150 crickets in and around the small crevices near "The Gap," an area on the northwest side of the island.  Perhaps these small crevices are used as refuges during dispersal events.

A small crevice that held several crickets
Although we didn't find the Lost World Cave, this spelunking expedition taught us a bit more than we knew before about the Farallon Cricket's behavior and demography.

Friday, November 18, 2011

First Island Records and other fun birds

Southeast Farallon Island has one of the largest species lists for such a small area at this northerly latitude. With over 40 years of ornithological scrutiny and a list of 418 species, adding a new one to the list has gotten increasingly difficult.  Many of the species that are rare to California have been seen here already.  However there are numerous possibilities that have yet to make their debut in the state, and we ponder frequently which of these will show up here next.  Several other species, such as Western Scrub-Jay and American Dipper, are common in the state, but because of their more sedentary nature are unlikely to ever cross 20 miles of inhospitable ocean.  Although this latter group does not have the same exotic appeal as the former, long-time Faralisters are just as interested in this group. 

One group that many Faralisters struggle with are ducks.  Other than Surf Scoters, ducks seem to shun flying this far off shore.  Three merganser species are commonly seen California, but only one, the Red-breasted Merganser, had been seen by Faralisters prior to today.  Of the two remaining, Hooded and Common, Hooded seemed slightly more likely just because they are a longer distance migrant.  On November 18th, though, Oscar Johnson spotted a Common Merganser in basic plumage just offshore.  We all ran down to the East Landing to document this new species.  Sam Roberts managed to get a few decent photos that clearly distinguish this merganser from the similar Red-breasted, but unfortunately it flew just before we could get even better photos.  From Sam's photos, the clear white chin patch is cleanly demarcated from the dark throat, and the dark throat has a clean, straight demarcation below against the mostly white breast.  Furthermore, the bill is thick-based and is bright orange along the culmen (or top edge).  Red-breasted Merganser has a thin bill with a dark culmen and has a blurry throat with no clean-cut pattern.  The Faralist now stands at 419!

In addition to this first island record and the previously mentioned Short-tailed Albatross, we have seen several other interesting birds.  October 25th was a particularly nice day with light west winds and 5-10 miles of visibility.  A Summer Tanager and female Black-throated Blue Warbler were briefly seen at the lighthouse, but of greater interest were the island high count of eleven White-throated Sparrows and the long-returning Say's Phoebe, who we now refer to as Simon.  This phoebe was first banded in 2007 and has returned to spend its fifth winter on the island.

In addition to the above mentioned species, we also enjoyed two Swamp Sparrows and a rarely captured Rock Wren.  A few of these wrens typically over-winter every year, but they rarely come near our nets since they are not attracted to the few trees where the nets are located.

On November 1st, we were graced with a second Yellow Palm Warbler in just two years.  Western Palm Warblers are fairly common here during the fall, but the more easterly Yellow Palm is a very scarce migrant to California.  As the common name implies, Yellow Palms have more yellow than Westerns, in particular on the throat and the supercilium (or eye brow).  Prior to last year's Yellow Palm, this subspecies had not been adequately documented from the Farallones.

Here are two images of Western Palm Warblers for comparison:

November 3rd proved to be another good day for migrants with an Eastern Phoebe, a male Black-throated Blue Warbler, and a record late Pectoral Sandpiper; the previous late date was 23-Oct. A second Eastern Phoebe made an appearance the next day.

Also of interest were a few odd birds that had some of us scratching our heads such as this Herring Gull.  American Herring Gulls (smithsonianus) typically have more solidly dark back feathers and wing coverts.  The anchor patterns on the back feathers, checkered wing coverts, and tail pattern (not visible in this photo) are suggestive of the Asian Vega Gull, but the pale bill base, heavily barred undertail coverts, smudgy head streaking, and anchor patterns this early are not typical of Vega.

Another gull that caused some excitement was this bird, which looks to us like a Slaty-backed Gull, a largely Asian species which is as-yet unrecorded on the Farallones. Some aspects of the plumage gave us pause as to whether it was a pure Slaty-backed, including the limited streaking around the eye, the apparently rather pale mantle, and the limited "string-of-pearls" in the primaries (not shown in the photo below). Communication with birders in Japan, where this species is regular, furthered our belief that this bird is within the range of a pure Slaty-backed Gull. We will submit this record to the California Bird Records Committee to see if they endorse the identification.

A Yellow-rumped Warbler intergrade between Audubon's and Myrtle spiced up our day.  This individual shows the eye arcs and lack of a supercilium typical of Audubon's, but the white throat wrapping up and around the back of the auriculars (or ear coverts) is more like Myrtle.

Two Horned Larks of different subspecies hobbled about on the gravelly area of the Marine Terrace.  One was quite pale, while the other was more richly colored.

Brown Creepers rarely show up on the island, but when they do, they frequently are found hanging around the cypress trees.

On 8 November, a Xantus's Murrelet turned up in Fisherman's Bay.  This species is in the same taxonomic family as the several species of alcid that breed on the Farallones (Pigeon Guillemot, Common Murre, Rhinoceros Auklet, etc.), only this one breeds on the Channel Islands off southern California.  There are only about 25 records of this species for the Farallones, and they usually show up during warm water El Nino years.  Why one would show up in these frigid waters during November will just have to remain a Farallon mystery.

Just as impressive was the return of a Golden-crowned Sparrow with the color-band combination silver on the left and orange over orange over yellow on the right.  We abbreviate this combination as S/OOY, which has become this bird's name.  We first banded this bird in 2005 and have seen it every year since!  Look at that crown!  Go S/OOY!

A lovely male American Kestrel also showed up on this calm day.  It has remained on the island for the past week to help rid the island of the introduced House Mouse.

Lastly, a juvenile Indigo Bunting showed up the following day.  Juveniles of this species can be distinguished from the more common Lazuli Bunting by the more uniformly dark rufous-brown upperparts, less contrasting wingbars, and more uniform buff wash below with blurry streaking.

Monday, November 07, 2011

First Short-tailed Albatross in 124 years!

On 6 November, 2011, PRBO biologists documented the first Short-tailed Albatross from the Farallon Islands in 124 years. This species used to be the most common albatross seen along California’s shoreline. Historical accounts mention that it was “numerous” in nearshore waters, including around the Farallon Islands. Short-tailed Albatrosses, however, did not breed on the Farallones or anywhere near the California Coast. In fact, its primary breeding grounds were located on islands scattered across the western Pacific Ocean south of Japan and in the East China Sea.

Short-tailed Albatrosses make an amazing 2,500 mile migration from their breeding grounds off Japan to the California Current and the Gulf of Alaska to take advantage of the nutrient-rich upwellings in these regions.  They feed largely on squid and fish on the surface of the ocean, and are often found feeding on the offal discharged by fishing boats. They are truly impressive birds, with a wingspan of seven and a half feet, making it the largest albatross regularly occurring in the northern hemisphere. Juvenile Short-tailed Albatrosses are solidly dark brown and take an estimated six years to attain the largely white plumage and golden head of a breeding adult. 
Short-tailed Albatross mated pair, probably at Torishima Island.
Juvenile at Cordell Bank, Marin Co., 16 Sep 2009 (Photo by Tom Blackman)
There are two other species of albatrosses that occur in California waters to find food, the smaller Black-footed and Laysan Albatrosses. Both of these species, though, are relatively common in California waters, and in fact, the Black-footed Albatross is seen regularly from Southeast Farallon Island.

During the second half of the 19th century, feather hunters killed an estimated 10 million Short-tailed Albatrosses on the breeding islands. Due to this intense hunting pressure as well as two volcanic eruptions at its primary breeding colony on Torishima, the species was thought to be extinct by 1949. Thankfully, a few dozen immature birds survived at sea away from the breeding islands, and with a hunting ban in place, the species returned to Torishima and began breeding again in 1954. Coordinated conservation efforts by the Japanese, Canadian, and US governments have allowed the species to undergo an amazing recovery, so that the population estimate as of 2007 has increased to approximately 2,500 individuals. 

Breeding colony of Short-tailed Albatross at Torishima Island 
The majority of these birds breed on the Torishima and Mukojima islands off Japan, but in the last ten years a few individuals have shown signs of breeding on Kure and Midway Atolls in the Northwestern Hawaiian Islands, and just last year a pair successfully fledged a chick on Midway. Despite these successes, Short-tailed Albatrosses are particularly susceptible to becoming by-catch in the long-line fishing industry and consuming plastics that they mistake for food, which can directly kill them or cause them to die from malnutrition. Both of these threats are hampering efforts by conservationists to recover this species.

As a result of the population increase over the last 60 years, Short-tailed Albatross has slowly started to reappear in California waters, with the first record since about 1900 being a bird seen 40 miles west of San Clemente Island on 28 August 1977. Since that date there have been a total of 33 records in California waters, 15 of which have occurred since 2007, and two of which were seen in San Francisco County waters. However, the last time that a Short-tailed Albatross was seen at Southeast Farallon Island was when one individual was collected by an ornithologist on 20 March 1887.

So, you can imagine the excitement when Oscar Johnson spotted a large, dark brown albatross with a huge, pink bill flying behind a fishing boat that was offloading offal about two miles west of the island. After a few moments of disbelief, he yelled into the radio to notify the rest of the island’s residents (Jim, Liz, Sam, and Megan), who ran up to the lighthouse to witness a species that barely escaped the maw of extinction.  With high-fives all around, we watched an immature Short-tailed Albatross fly to within a mile of the island before turning around and heading back west to the deep water zone where albatrosses are normally found.

Immediately after seeing the bird, Oscar sat down and sketched it in his notebook and wrote down some details on how it was identified. Here is a scan of that drawing.