Things are perking along at the Airpark Lagoon in Courtenay, British Columbia. Always a good spot for winter birding, at the large viewing stand on the eastern side of the lagoon I was watching a group of Barrow’s Goldeneye when I noticed a group of shorebirds foraging in the long grass directly below the platform.
Closer examination revealed that the birds were Long-billed Dowitcher (Limnodromus scolopaceus), a bird that is difficult to separate from the Short-billed Dowitcher (Limnodromus griseus). One would think that telling these two birds apart would be easy – after all, one has a long bill and the other a short, right? Unfortunately, bill length in dowitchers is notoriously variable and there is much overlap between the two species.
Consultation with several bird books back home pointed to some identifying features that can be used to separate the Long-billed and Short-billed Dowitcher. The Sibley Guide to Birds suggests field marks to look for include the Long-billed’s darker looking tail and grayish tertials with narrow rusty edges (the Short-billed has a more barred look). These birds definitely do have grayish tertials which leads to an identification as Long-billed Dowitchers. Peterson’s field guide to Western Birds states that they are “more easily separated by voice, provided they speak up.” Not the case yesterday.
I did find a good website by Greg Gillson that is helpful to those trying to identify these two very similar birds. Identification of Dowitchers in the Pacific Northwest provides some more subtle characteristics to look for. According to Gillson, the Pacific subspecies of Short-billed Dowitcher has dark barring on the tail that is very similar to that of the Long-billed Dowitcher and so cannot be used to reliably identify the type of bird.
One of the features that Gillson states to look for is the colour and markings on the breast – Long-billeds in the fall can be identified by worn breast markings and a smooth reddish colour on the underparts. Interestingly, at this time of year on West Coast the Short-billed Dowitchers have already moved through with migration occurring between late June and mid-August. Long-billed Dowitchers tend to migrate later through July and into September and they may stop in the Pacific Northwest on their way south making it more likely that these dowitchers are Long-billed.
It was fascinating to see so many Long-billed Dowitchers and to watch them feeding in the grass and shallow mud of the lagoon. I was amazed at their ability to blend into the background and at how difficult it was to see them when they weren’t moving. I was reminded about how important it is to take the time to observe the world around us – there are discoveries waiting every time we step outside!
If you have any other helpful hints or suggestions for resources that would make identifying these shorebirds easier I’d like to hear from you!
Regional BC Breeding Bird Atlas coordinator and former Canadian Wildlife Service regional director Art Martell adds these field marks to look for:
- Long-billed – average larger, rounder back and belly, with longer bill
- Long-billed – retrices with black stripes wider than white
- Short-billed – retrices with white stripes wider than black; but much overlap and tend to be darkest in caurinus
- not safely separable in basic plumage
Adult – fall migration
- Long-billed – underparts uniformly brownish red, greater contrast between back and underparts
- Short-billed – almost always has a white belly and undertail coverts
Juvenile – fall migration
- darker above
- tertials plain internally
- underparts duller, grayer throat and breast; streaks lacking
- less rusty overall
- tertials well marked internally
- upper parts richly washed reddish orange; fine dark streaking
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