Tuesday, August 4, 2015

Surveying Whitewater Lake IBA

On August 2, 2015, Jo Swartz and I surveyed the Whitewater Lake Important Bird Area (IBA), tallying shorebirds and other species both inside and near the IBA.  We found 102 species including 22 species of shorebirds plus a few more en route. Some highlights and high counts for the IBA are given below. I also decided to use this chance to talk a little bit about the area and its birds.

Whitewater Lake is a closed basin and has alternated from periods of being bone dry (a few decades ago) to being flooded well past its former shoreline as is the current situation. When I arrived in Manitoba in the early 2000s, the lake was slowly filling back up again and was very shallow at that time. I remember when the whole basin had a shallow layer of water, that the shorebird flocks numbered in the tens of thousands. I recall watching with friends as a Prairie Falcon put up a massive and dense cloud of shorebirds. Then by the mid 2000s, as the lake was getting deeper and the emergent vegetation growing tall in many areas, the lake seemed transformed from a shorebirding destination to a site for rare long-legged waders. In 2006, Ron Bazin and I confirmed breeding of White-faced Ibis in Manitoba for the first time and many rare herons began appearing more and more regularly. In addition to the White-faced Ibis, Great Egrets and Cattle Egrets established colonies and Snowy Egrets were eventually confirmed breeding by Ken De Smet in 2011. All this high water and the great fetch of the prairie winds eventually breached the dyke structures that were built to create cells in the southeastern corner of the lake, such that by 2014 they were “united” with the lake and the cattail beds largely drowned out. The road to the main viewing mound is collapsing and is not currently safe to drive. The shorebirds are no longer as concentrated as they used to be and water logged fields one or two miles from the lake are mow the best places to look for them. Although these areas are not currently within the IBA, some of the wetland-upland complexes around the lake represent important ephemeral habitats that host great diversity and concentrations, as well as high productivity.

To give you a bit of a sense of the lake and its turbulent history , here are a few photos I took on this trip. The first shows what used to be a house on road 19N. The whole road has been washed away, although its slightly raised and compacted bed has allowed the cattails to take hold in what is otherwise a flooded extension of the lake approximately 2 km from the former shoreline.The second photo gives a wider angle of the same area.

This photo shows a former road allowance / “farm road” that has been eroded away and continues to be ground down by the wind and wave action.

The areas well away from the lake proper are now the best shorebird habitat as shown in the photo below (the shallow basin of the main lake used to be THE place in the early 2000s):
Not so very long ago, many of the long-legged waders that are now considered to be Whitewater Lake specialties were mega-rarities in Manitoba. This changed in the mid 2000s. One of the areas special birds (considering they are extremely rare anywhere else in Manitoba) is Snowy Egret and on August 2, we were treated to great views of this individual. I thought at first that this bird might be a juvenile as I saw the long yellow stripe up the back of the leg but the nuptial plumes of the rear crown and lower back made me realize this must be an adult.

Although they have been difficult to find this year, Whitewater Lake is THE place in Manitoba to find Cattle Egret as well. I didn’t manage to get any photos of the Cattle Egrets we saw on this surveying effort but I have added this photo taken last year.

It should be mentioned that these smaller egrets are still rather uncommon and by far the most common egret breeding at Whitewater lake is Great Egret (we only counted 35 on the day but many more were likely hidden in currently inaccessible areas). This photo was taken the following week:

Before proceeding to some of the highlights of the survey, it is worth a little flashback of some of the many rarities that have graced Whitewater Lake, particularly in the heron family. They included frequent sightings of Little Blue Heron as shown here from a few years ago (in fact we wonder if they may have bred here):

And other rarities have included Tricolored Heron and Yellow-crowned Night-Heron as shown here:

Of course there are also lots of the "regular" herons. This American Bittern tried the you-can't -see-me pose as we were surveying this Sunday. In recent years, Least Bittern, a species that seems to be expanding both northward and westward in Manitoba, has also been on territory in the lake's now extensive reed beds. Black-crowned Night-Heron also breeds here and we counted 59 on the day including some juveniles.

Another of the star attractions of Whitewater lake is White-faced Ibis. We counted 145 of these beautiful birds (quite the change from 10 years ago when this species was an RBA alert!). This photo shows a small flock and a little bit of the plumage variation at this time of year, especially how the facial pattern begins to change in late July as they transition from breeding to non-breeding plumage. White-faced Ibis is now the common ibis at Whitewater lake; however, Glossy Ibis has also recently become almost annual (especially in June) so one has to be very careful in the later summer and fall with the ID of Plegadis ibises (all of the birds in this photo are White-faced Ibis). In addition, there is a relatively recent record of White Ibis.   
As you would expect with a wetland complex of this magnitude, rails also abound here. It was late in the year to get a good count on rails (they are less vocal now),  but we saw and heard both Sora and Virgina Rail while counting. This photo of a Virginia Rail was taken at the lake earlier this year. Yellow Rail also occurs further from the lake in sedge meadow habitat. By far the most ubiquitous member of the rail family is American Coot and we counted 4,592 of them on the day.

August is a difficult time to be counting waterfowl when many are far from the observer and in eclipse plumage but we did our best. An example would be a day-total of 2,575 Mallards. American White Pelicans are easier to count and our tally was 1,211 on the day, although this is not a breeding site for this species. We counted 199 Western Grebes including many with young as shown in the two photos below, although the real highlight was seeing a Clark's Grebe with young (a little too far for good photos). In the five years of fieldwork  for the Manitoba Breeding Bird Atlas, nobody managed to get confirmed breeding evidence of Clark's Grebe so this was a little bitter-sweet!

Even though Whitewater lake is not as good for shorebirds as it was 10 years ago, this is still an important breeding site for "prairie wetland species" such as American Avocet, Marbled Godwit, Upland Sandpiper, Willet and Wilson's Phalarope. Naturally, this is also a major staging area for thousands of arctic breeding shorebirds. In late July and early August, the American Avocets gather in large flocks, presumably a mix of local breeders and migrants, and can offer an impressive spectacle when they form tight flocks feeding in a "vortex". On this day our count of  3,123 American Avocets included a few such feeding flocks. The first photo below shows one of these avocet swarms but because the views were distant I have added three photos taken at Whitewater Lake last year to illustrate this behaviour.

The most numerous shorebird on this count was Stilt Sandpiper (3,291 in total), so I have included a few photos of some of their flocks below. In each case, these photos only show a tiny portion of a larger flock. If you look closely you may pick out a few other shorebirds such as Wilson's Phalarope and Semipalmated Plover in the mix. The third most abundant shorebird species (after Stilt Sandpiper and American Avocet) was Short-billed Dowitcher  with a count of 2,223 but there were more Limnodromus sp. and some Long-billed Dowitchers as well. If you look closely at the fourth photo in this blog post, you may notice a dark band in the darker blue water in the background, which is a flock of dowitchers. We also had a good count of Wilson's Phalarope with 843 including many juveniles. Two small flocks of 14 Hudsonian Godwits were a special treat as they are not so easy to find here at this time of year.

One of the biggest highlights in our total of 22 shorebird species was Buff-breasted Sandpiper. This special bird is declining in number, causing concern. They breed in the high arctic and migrate all the way to the grasslands of southern South America. They are not easy to find in southern Manitoba any more and Whitewater Lake in early August represents the best chance of finding them. They like "short grass" habitat types such as wet fields, stubble fields, sod farms, and large flats and are sometimes found alongside American Golden-Plover (another high arctic breeder heading to the South American grasslands) and other shorebirds that frequent these habitats. This means that they are not often close to the water's edge where the other shorebirds are and you have to make an effort to find them. On this day, we spotted two on open mud far back from the main shorebird flocks. See if you can spot one of them in the first photo below. If that doesn't work, try the second photo which shows three individuals or the third photo for a closer look. The last two photos were taken in northern Manitoba and not at Whitewater Lake but I have used them to give you a sense of this beautiful bird and how they blend into their habitat.

There are also often raptors here and at this time of the year both Peregrine and Prairie Falcons like to put up the shorebird flocks. On this day we only recorded one Peregrine; however, the following week Tim Poole and I watched this Prairie Falcon soaring above us:

Of course, there is a lot more to Whitewater Lake than the birds shown here. There are also many passerines to look for and I leave you with one simple photo of a Yellow-headed Blackbird to summarise the rest of the amazing biodiversity at this Important Bird Area.

I hope you enjoy this brief introduction to this Manitoba hotspot. Please contact me with questions! There is also another recent article of interest on the lake at: http://manitobacooperator.ca/country-crossroads/whitewater-lake-region-under-threat/

1 comment:

  1. I have enjoyed your report and found it very informative. On June 4, 2001 myself and other birders identified the Curlew Sandpiper at Whitewater Lake as this was a rare sighting,


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