Following the early August blitz at Whitewater Lake, we decided to give it another go and see what else we might turn out in this critically important area on Sunday August 27th. Manitoba IBA Coordinator, Tim Poole gives an overview of proceedings.
For most bird species, a good look in the scope is enough for a successful identification. However the fall can leave even the best birders sometimes scratching their head. Fall warblers and vireos can be taxing for most but there are always little giveaways to help bring about a successful identification. Sharp-shinned versus Cooper’s Hawk can keep a whole group on Facebook debating for days.
Shorebirds can also be tough in fall. In most cases, there are telling features which help us to get the correct species in the end. In the case of the dowitchers though these features are often difficult to draw out as they gather in ‘large carpets’ of birds. The adult plumage in fall becomes very worn and given these shorebirds can flock in groups of several thousand, they can seem almost indistinguishable between two species, Long-billed Dowitcher and Short-billed Dowitcher.
Now, these are two distinct species and there has been considerable work done on advancing our knowledge of the key identification differences between these two species. There is an excellent pdf and summary of a talk on exactly this matter on the Surfbird website.
Another resource made available by Christian Artuso is this table outlining the physical differences between the two species. Dowitchers comparison
Interesting enough, juvenile birds in fall tend to be easier to identify in the field than the worn-looking adults. This is due to distinctive differences in the tertials (the innermost secondary wing feathers) which are prominent on the rear of the bird when stationary on the ground. The tertials of the Short-billed juvenile has orange bars, whereas the Lon-billed juvenile has grey tertials with rusty edges.
In reality the best way to count these large flocks is by ear. The Short-billed Dowitcher call is a lower pitched kewtutu and the Long-billed Dowitcher is a higher pitched, sharp series of kik-kik-kik. However in a flock of 2000 dowitchers, one call from one Short-billed Dowitcher is not going to be enough to allow you to identify the entire flock. So we need some help!
Thank goodness then for birds of prey! Fall is also the time for large numbers of raptors to visit and Sunday was no different. For example, in the northwest corner and along the south of the lake, Peregrine Falcons flushed flocks of dowitchers. It was Bald Eagles and Northern Harriers doing this duty along the northern edge of the lake. In one case, over 2000 Long-billed Dowitcher were flushed by an eagle, giving Eric, Louise and myself a single count of this species where previously it was difficult to distinguish between individuals in a carpet of birds.
This ultimately led to a total of 2,196 Long-billed Dowitcher, 350 Short-billed Dowitcher and 3357 unidentified dowitcher species, just going to show that most flocks were just not calling enough to identify. The long-billed figure will actually trigger the 1% global concentration on the IBA tables in future – another new species for Whitewater!
As for the remainder of the blitz we had 19 volunteers out around the IBA in 5 groups. Each group was given a section to complete, recording every individual bird within this area in the allotted time.
Group 1 consisted of Eric Smith, Louise Buelow-Smith and myself. Our challenge was to get into some of the corners around 19N and 121W and then see if we could access some of the other road allowances. Our early Peregrine and large flock of dowitchers was a precursor of things to come. A large flock of 28 Cattle Egret was a surprise on 19N. Cattle Egret is another which has become a more recent breeding species for Manitoba and is even now spreading out towards Oak Lake, much like the White-faced Ibis. It is though still known as a Whitewater specialty.
Another species of note in this section was the American Avocet. Three large groups were located with a count of 1,795 in total in this one section. Not bad for late August! The northeast is an interesting section, much of it, including the old WMA now inaccessible due to the high lake levels.
Group 2 was Lewis Cocks, Ken Simonite, Wally Jansen and Robb Nickel. They covered an area in the southeast up to the main mound. Highlights included a lifer Baird’s Sandpiper for Ken.
They also counted 2 Snowy Egret, another specialty for Whitewater, contributing to a total of 63 species.
In the southeast, Christian Artuso, John Hays and Patricia Rosa spent much of their time on foot around 128W. This area of Whitewater seems to contain phenomenal numbers of birds including 1,000 Northern Pintail, 4,100 Mallard, 1,675 Western Grebe, 703 Double-crested Cormorant, 603 American Coot, 350 Eared Grebe and 420 Black Tern.
Shorebird totals were very impressive. 83 Baird’s Sandpiper, 187 Least Sandpiper, 830 Semipalmated Sandpiper, 325 Short-billed Dowitcher, 125 Long-billed Dowitcher and 32 American Golden Plover. There were 18 species of shorebird in total. Rarer both here and elsewhere is the Buff-breasted Sandpiper. This High Arctic species is listed as Near Threatened by IUCN and winters in the pampas of South America. In common with its open winter and breeding habitats, on migration this is a species often found in short open vegetation – the most well known spot in Manitoba currently are the sod fields north of Oak Hammock Marsh and earlier this August at Riverton Sandy Bar. Unlike other North American shorebirds, the Buff-breasted Sandpiper uses a lek system of mating where males defend small display territories. Females select a mate and then nest and raise their brood elsewhere.
The gentle looking Buff-breasted Sandpiper (third photo with Least Sandpiper). All photos copyright Christian Artuso.
In group 4 we had Dave and Pat Wally. They counted 111 Snow Geese, huge numbers of Bank Swallows (although Tree Swallow appeared more numerous overall this time). They also counted a couple of Black-bellied Plover but this area did not turn up the large numbers of shorebirds that it did in the spring – it did not in early August either. However, there are tall cattails which may be blocking the view of our volunteers in this part of the lake. American Bittern was another species encountered. Margaret and Joan from Pierson and Lyleton arrived later but still had fun birding and joined us for lunch.
Finally Glennis Lewis, Jen and Anna Wasko monitored the northwest. 6 year old Anna moved on from counting Northern Shovellers and took to counting the numerous American Coots – 517 in total. 116 Western Grebes were counted around Sexton’s Island – adding to another huge total. Shorebirds were very thin on the ground, the ephemeral wetlands were dried out and the best places were along the lake shore which is not always accessible.
We will publish a full summary of both the 6th and 27th August blitzes but here is the total for the blitz. Large totals to highlight were 5,507 Mallard, 1,846 Northern Pintail, 2,050 Western Grebe, 4,140 American Coot, 1,938 American Avocet, 892 Semipalmated Sandpiper, 2,196 Long-billed Dowitcher, 4,381 Tree Swallow, 1,423 Bank Swallow and 768 Yellow-headed Blackbird.
|American White Pelican||540|
|Great Blue Heron||19|