Sunday, July 26, 2015

The Start of the Shorebird Migration

July is a great month to spend at the beach and observe the amazing shorebird migration. In Metro Vancouver, we are lucky to be situated along the Pacific Flyway in an area that offers some of the country's best shorebird viewing opportunities: the Fraser River Estuary. The Fraser River Estuary is designated as a site of Hemispheric Importance in the Western Hemisphere Shorebird Reserve Network (WHSRN). Several million shorebirds pass over the estuary each year in migration and tens of thousands remain for the winter. Shorebirds form enormous concentrations at such key staging areas along their migration route. Each area provides an abundance of food resources that enable birds to quickly replenish their energy reserves and complete the next leg of their journey. These staging areas underpin their entire migration system, but also lend great vulnerability to their users. Such enormous concentrations of birds at relatively few, widely spaced locations break the usual relationship between a species' abundance and its immunity to extinction, while highlighting the conservation value of these special places.

Western Sandpipers lead the shorebird migration throughout much of the fall on the Fraser River Estuary.
Semipalmated Sandpipers move through in small numbers and their migration through our area will largely be over by the end of August. 
Least Sandpipers forage in small flocks in drier and more vegetated areas compared to Westerns, which dominate the open mudflats.

Fall shorebirds can make or break a big year in Metro Vancouver. There are numerous locally uncommon species that require determined and routine circuits of the local shorebird hotspots to see, plus almost endless possibilities for unexpected vagrants.This year, the fall shorebird season started off slowly with a pair of Pacific Golden-Plovers on July 19 being the only notable species I've observed thus far. Naturally, five days after leaving town for work, the first truly rare shorebird of the season showed up on July 24: Bar-tailed Godwit. I'm hoping its a really tired and hungry one and needs at least another 9 days to build up its fat reserves.

#228 - Pacific Golden-Plover - July 19, 2015 - Boundary Bay, BC. 

"koWIT" said one golden-plover to the other. (Translation: "race you across the Pacific".)

Being just a spectator from afar for the remainder of July, it seems 228 will be my month-end total. While finding another 22 species in five months doesn't initially seem like an unreasonable prospect, reviewing my "Target Species" on eBird suggests fairly limited opportunity. Here are the 30 most frequently reported species in Metro Vancouver between now and end of December that I still need for my year list.






Saturday, July 4, 2015

June: The Halfway Point

June is a good month to catch up to any breeding birds that may have been missed during spring migration. Some years it can be a good month for vagrant eastern passerines holding territory, but this year did not produce any such surprises. However, there are always a few scarcities that require a concerted effort to see.

American Redstart is one of these. Pitt Meadows is really the only reliable location within the Vancouver checklist area where redstarts occur annually on territory. There are usually one or two territorial males somewhere along the Grant Narrows Nature Dyke or along the Pitt River Dyke south from the Pitt Lake boat launch. This year, a walk along the Pitt River Dyke yielded 3 singing males.

#223 - American Redstart - June 7, 2015 - Pitt River Dyke (a.k.a. Catbird Slough), Pitt Meadows.
Another pseudo-rarity I was happy to catch up to was House Wren. I find their near absence in the Vancouver checklist area quite puzzling considering they are common in a variety of habitats across their range, and are not an uncommon breeder in urban areas of southern Vancouver Island and the Gulf Islands. I observed this one on private property in the eastern reaches of the Vancouver checklist area.
#225 - House Wren - 9 June 2015
Perhaps somewhat counter-intuitively, June can also be an interesting month for shorebirds. It is often difficult to know whether these birds are coming or going, but that is part of the appeal, which also lends tantalizing possibility. During the first few days of June, some of the straggling northbound migrants are still passing through our area. Some first year birds do not migrate all the way to their breeding grounds and spend their first summer on their wintering grounds or somewhere in between.   Small flocks of summering Black-bellied Plovers in Boundary Bay and Roberts Bank are one such example. Many of these birds skip their alternate moult and wear their subdued winter colours all summer long while their adult counterparts are looking spiffy in the high arctic. Straggling migrants will often associate with small concentrations of summering shorebirds, like the adult breeding plumaged Red Knots at Brunswick Point, making these flocks worthwhile to check.

#226 - Red Knot - 13 June 2015 - Brunswick Point, Delta. Look for them in the vicinity of the pink flag. 
By late June, though just a trickle, southbound migration is already underway. Shorebirds that were unsuccessful in their breeding attempts are the first to appear, then adults that 'got the job done' following later in July. I usually start shore birding early, often too early, but sometimes the early season has its surprises. Kicking off my fall shorebirding on June 27, I arrived at Boundary Bay with Mel to find Kevin Louth looking at a Ruff!

#228 - Ruff - 27 June 2015 - Boundary Bay, Delta.
Excitement slowly gave way to concern, as we noticed this bird sporting colour bands. Resighting colour-banded shorebirds is fairly uncommon, let alone when they are on the wrong side of an ocean! (Consider probability: what are the odds of a few randomly selected [banded] individuals from a much larger population ending up straying off course?)  However, this in itself would not have been such a concern if we didn't know that there was a captive breeding program at Simon Fraser University, only some 20 km away. In fact, the captive breeding program at SFU is the largest Ruff aviary on the planet, and by contacting the appropriate researchers we received confirmation that our bird had escaped their captivity. You can read more about SFU's Ruff study here. Unfortunately, this meant that this Ruff was removed from my year list as promptly as it was added. Meanwhile, I'm hoping a wild Ruff will take the scenic route south later this fall.

Count update: 227 species on June 30.