Posts Tagged 'Long-billed Dowitcher'

Reifel: August 21st 2010

With my exams finished and the summer semester all wrapped up I was free to head out birding on Saturday. After checking out the tide and finding it to be suitably out ‘till around six pm, it was an easy decision to head to Reifel Bird Sanctuary in an attempt to catch some shorebird activity on the westernmost ponds where the low water level would attract them to feed.

The action kicked off in the parking lot with two Peregrine Falcons arriving from the south. I later caught up with one of them perched atop a tree inside the sanctuary…

Undoubtedly the falcons were here for the shorebirds as well, though I’m sure they weren’t here just to watch them. These birds often sit in a location with a good field of view and wait for an injured or sometimes overtly conspicuous bird to make itself known; most other birds are allowed to continue without contest (1). I did not get to witness either of the falcons attempt a capture but the shorebirds and waterfowl were quite skittish and frequently took flight to change location within the ponds.

Lesser Yellowlegs were the predominant species of shorebird at the tidal ponds. Greater Yellowlegs, Long and Short-billed Dowitchers, Stilt Sandpipers, and Red-necked Phalarope were also present; all actively engaged in finding food.

The three Stilt Sandpipers spent most of their time foraging with the Dowitchers where their rapid “stitching” feeding motions could be directly compared with the slower “sewing machine” action of the Dowitchers. Both species would often associate in a loose, line abreast formation and proceed forward together. As the line moved ahead each bird would slowly begin to break formation as, I assume, they each attempted to find a larger concentration of prey. After the flock was flushed into flight the birds would resettle, form the line again, and continue.

Another great day of birding at Reifel Bird Sanctuary; the fall shorebird migration seems to be well underway.

Reference:

  1. White, Clayton M., Nancy J. Clum, Tom J. Cade and W. Grainger Hunt. 2002. Peregrine Falcon (Falco peregrinus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.proxy.lib.sfu.ca/bna/species/660doi:10.2173/bna.660
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Maplewood: October 13th 2009

I was not in the mood for homework today and so I decided to head out birding for an hour or two. When I arrived at Maplewood the tide was out so I decided to check out the western area first. Nothing much was going on until I got to the largest of the ponds (the one that usually has ducks). I spotted a Sharp-shinned Hawk flying above the trees to the east; it was being chased by two Northwestern Crows who managed to get a few swipes in before the hawk ducked into the treetops.

The two Long-billed Dowitchers and three of the Greater Yellowlegs that I observed on October 10th and 11th were still present on the mudflats and actively engaged in foraging for food.

On my way out I had a look at the birdfeeders hanging in the fenced off maintenance area and immediately noticed a single Evening Grosbeak. Unfortunately it flew off before I could get any pictures. Song Sparrows, Black-capped Chickadees, Dark-eyed Juncos, House Finches, and a few Spotted Towhees were also at the feeders.

Maplewood: October 11th 2009

Thanks to the long weekend I was able to get out birding for the second day in a row. The tide was just beginning to recede when I arrived at Maplewood flats and so I was able to get some excellent views at the four Greater Yellowlegs and one of the Long-billed Dowitchers present.

It was quite amazing to watch the Greater Yellowlegs in action. They were very efficient at capturing prey. I observed one of them pull some sort of worm out of the mud and then a couple seconds later another had a small fish in its bill and shortly after that a different individual captured a crab.

Well I definitely have something to be thankful for. I hope your thanksgiving was as good as mine!

Maplewood: October 10th 2009

I spent a few hours at Maplewood yesterday and there were several good birds active on the mudflats. Besides the large numbers of American Widgeons several Bufflehead and a single female Lesser Scaup were diving to the southeast of the viewing area. On saltwater Lesser Scaup and Bufflehead predominately consume invertebrates such as crustaceans, and molluscs (Gauthier 1993, Austin et al 1998). Green-winged Teal were also present close to shore and I spotted a lone Northern Shoveler intermixed with a raft of American Widgeon. Various gull species (Mew, Glaucous-winged, Thayer’s, and Ring-billed) were on shore and in the water.

Two Greater Yellowlegs were foraging near the Blueridge Creek outflow in the northern section of the mudflats and two Killdeer were also at the same location. During the day Greater Yellowlegs acquire food through swift stabs at the surface. On mudflats their main prey is small aquatic and terrestrial invertebrates (Elphick and Tibbitts 1998).

Shortly after sighting the Yellowlegs I observed two Long-billed Dowitchers foraging in classic sewing machine like feeding behaviour in the shallows. Dowitcher’s feed primarily on polychaetes, bivalves, and amphipods present in soft muddy substrate (Takekawa and Warnock 2000). They detect their prey through the use of tactile receptors known as Herbst corpuscles at the tip of their bill (Burton 1972).

Both Short and Long-billed Dowitchers are in non-breeding plumage during fall migration making identification in the field very difficult. In addition to consulting numerous field guides I have found this article by Cin-Ty Lee and Andrew Birch on the surfbirds website to be particularly helpful.

I find it particularly interesting how the two species of shorebirds I observed yesterday differ in bill physiology and foraging behaviour and so can coexist on the same stretch of mudflat.

References:

Gauthier, Gilles. 1993. Bufflehead (Bucephala albeola), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.proxy.lib.sfu.ca/bna/species/067doi:10.2173/bna.67

Austin, Jane E., Christine M. Custer and Alan D. Afton. 1998. Lesser Scaup (Aythya affinis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.proxy.lib.sfu.ca/bna/species/338doi:10.2173/bna.338

Elphick, Chris S. and T. Lee Tibbitts. 1998. Greater Yellowlegs (Tringa melanoleuca), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.proxy.lib.sfu.ca/bna/species/355doi:10.2173/bna.355

Takekawa, John Y. and Nils Warnock. 2000. Long-billed Dowitcher (Limnodromus scolopaceus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.proxy.lib.sfu.ca/bna/species/493doi:10.2173/bna.493

Burton, P. J. K. 1972. The feeding techniques of Stilt Sandpipers and dowitchers. San Diego Soc. Nat. Hist., Trans. 17:63-68.