Saturday, November 17, 2012

From Mundane to Mega


Grasshopper Sparrow, Southeast Farallon Island, 10/24/2012.
A lot has happened since our last post, though certainly things have begun to slow way down since our peak migration in early to mid October.  This has been one of the best falls in the past several years in terms of diversity and numbers of birds, and despite a subsiding landbird migration, great birds have continued to surprise us including large seabird flights.  From the mundane to the megas, we've had it all in the past few weeks.

After Jim Tietz left for his two-week break at the end of October, passerine migration nearly came to a halt, much to our disappointment.  Nonetheless, we were able to find a few very rare birds for the island, including a Cooper's Hawk found by Ryan DiGaudio at the lighthouse.  Sharp-shinned Hawk is far more common than Cooper's.  While this is only the 30th record ever for Cooper's Hawk for the island, we've seen 6 Sharp-shinned Hawks already this fall alone.  A Common Goldeneye was also found by Lukas Musher on Maintop Bay at the Northern part of the island.  The goldeneye is only the 6th fall season record and 20th ever. 
Juvenal Cooper's Hawk, Southeast Farallon Island, 10/25/2012.  Note the protruding, relatively large head (causing the eye to look relatively smaller), and long rounded tail, which help distinguish this bird from Sharp-shinned Hawk.
A rather distant and bad photo of the island's 6th fall record of Common Goldeneye, 11/3/2012.
One of a few Lapland Longspurs we've had on the island this fall.  Lapland Longspur is our most common longspur species.
Some of the relatively more common, though still interesting, birds we saw during late October include Great Blue Heron, Short-eared Owl, Barn Swallow, American Robin (first of fall), Varied Thrush, Townsend's, Magnolia, and Chestnut-sided Warblers, Lapland Longspur, Grasshopper Sparrow among others, and a very late Blackburnian Warbler on November 2 was a great surprise as well.
American Robin, Southeast Farallon Island, 11/4/2012.
Jim Tietz still has all the luck, though.  After very few good birds during his absence, he was able to get two island birds upon his return to the island.  The first was the continuing Common Goldeneye found earlier in the week, and the second was a Horned Puffin, a lifer for the entire fall crew.  We immediately noticed the pale face and white underparts, and Jim pointed out that the pinched in base of the bill.  All of these features allow immediate identification, and differentiation from the more common Tufted Puffin.

In fact we've had a lot of good seabird activity over the past few weeks.  In late October we had a couple days where literally hundreds of Buller's Shearwaters moving by in under an hour of sea-watching.  Lot's of Sooty Shearwaters, more Pink-footed Shearwaters, the first Northern Fulmars and Black-legged Kittiwake (immature bird) of the season, and both Pomarine and Parasitic Jaegers were also present during these late October seabird flights.  More recently, on November 7, we had a huge flight of waterbirds including 2400 Pacific Loons (counted between about 2PM and sunset), 13 Common Loons, 2 Western Grebe, 2 Short-tailed Shearwater, 30+ Northern Fulmar, 9 Pink-footed Shearwater, 100+ Sooty Shearwater, 3 Black-vented Shearwater, 185 Cackling Geese, 410 Brant, 1 Green-winged Teal, 2 Red-breasted Merganser, 2 Pomarine Jaeger, 24 Boneparte's Gulls, and 6 Ancient Murrelets.  We also had the island high count of 7 Horned Grebes that day.
Two Pacific Loons fly past East Landing during the very large flight on 11/7/2012
One of the few Cackling Geese that stayed with us after the seabird flight on 11/7/2012
Landbird migration picked up a little when Jim got back as well, including a couple major rarities.  This adult male Slate-colored Junco was one of two of that species on the island on November 5th.

This first-year Rough-legged Hawk, our second of the year, showed up on November 6th, and has been with us ever since.  The features that help determine the age of this bird are the translucent patches on the primaries and relatively pale brown (versus the bold, dark brown-black of an adult) tail band and trailing edge of the wing.
Rough-legged Hawk, Southeast Farallon Island, 11/6/2012
Thayer's Gulls of all ages have begun showing up recently as well.  This Second-cycle bird, below, was found by Jim last week.  Note the small, thin bill, gently curved culmen, and round/dovey head that are all typical structural field marks of Thayer's Gull.  This bird is molting in gray feathers on the back, but has retained wing coverts making it a second-cycle bird.
Thayer's Gull, Southeast Farallon Island, November 2012
Another good find was an eastern Orange-crowned Warbler (subspecies: celata).  We more commonly get the Pacific subspecies (lutescens), which has a greenish head; whereas the Rocky Mountain (orestera) and eastern subspecies both have gray heads.  We determined that this bird was an eastern by its short bill, measured in the hand.
Orange-crowned Warbler (Oreothlypis celata celata), Southeast Farallon Island, 11/8/2012
Nora Livingston also found a Song Sparrow (actually a relatively rare bird on the island).  Oddly enough, the Song Sparrow was missing its entire left eye!  It's astounding that it made it this far with only one eye.  This particular bird probably represents one of the Song Sparrow races from the Aleutian Islands, as it was large, stocky, and long-billed with heavy brown streaking.

Song Sparrow, Southeast Farallon Island, 11/11/2012. Poor little fella'.
We were also pleased to see a male American Kestrel.
Our resident Common Raven left for a few days and returned with a friend.  Now we have two, a mated pair.
Common Raven, Southeast Farallon Island, 11/3/2012
One of our resident Peregrines, accidentally flushed off its kill, a first-cycle California Gull.
Owl numbers have increased as well, as is to be expected in late fall, with our season high counts of 2 Northern Saw-whet, 2 Barn, and 2 Long-eared Owls on November 16th.  We even got to band a Northern Saw-whet and a Barn Owl on November 11 in addition to our usual Burrowing Owls.
A Northern Saw-whet Owl roosting in one of the 3 trees on the island.  Saw-whets are notoriously tame, so liz actually picked one off its perch on 11/11/2012 and banded it.
Long-eared Owl, Southeast Farallon Island, 11/14/2012
Our most spectacular day recently was November 14th.  We saw two California Bird Records Committee species (CBRC; these are species that must be documented and reviewed before the record can be accepted).  The first was a Rusty Blackbird, a very rare bird in western North America.  Note the rusty edges to the tertials, buffy supercillium, relatively thin bill and short, thin legs, and overall rustiness.  There are only 14 records for the island, so some people might say it's a pretty good bird.
Rusty Blackbird, Southeast Farallon Island, 11/14/2012.
Another great bird we had that day was a hatch-year male Summer Tanager.
HY Male Summer Tanager, 11/14/2012
However, the best bird of the day was an absolute mega rarity.  Jim found the bird foraging near one of the houses, and quickly realized that it was a (¡¡¡)LITTLE BUNTING(!!!), a species from Asia that has only been recorded in California twice before (one of which is from this island).  Unfortunately he did not have a camera as he was wheelbarrowing salamander coverboards around, so he immediately radioed to the rest of the crew to get there ASAP with a camera.  By the time we got there, the bird had just flown.  We spent the next 30 minutes searching for the bird, but couldn't relocate it.  Luke finally relocated it in the company of a Pine Siskin, but we still couldn't obtain a photograph.  The bird then flew off, and was never to be seen again.  You can see our ebird checklist for the day, including Jim's description of the bird here.
Maggie, the Burrowing Owl intern, found this Ashy Storm-Petrel chick in a crevice on 11/14/2012.
We like bugs here too!  Check out some of our most common migratory insects.
Painted Lady, Southeast Farallon Island, November 2012
Variegated meadowhawk, Southeast Farallon Island, November 2012.  A truly beautiful specimen.
By Luke Musher

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.