This spring, volunteers and the staff of Manitoba IBA headed out to once again conduct International Shorebird Surveys at four IBAs: Oak Hammock Marsh; the North, East and West Shoal Lakes; Oak/Plum Lakes; and Whitewater Lake. Last year, dry weather altered the preferred habitat of shorebirds and this year was the same, although instead of dried up wetlands and ditches, flooded fields and higher water levels were the norm, creating an interesting survey period.

The Spring International Shorebird Surveys (ISS) are conducted between April 1st and June 15th with the peak of the season occurring between April 24th and May 16th. Using our protocol (adapted from the ISS Protocol from Manomet), four IBAs are surveyed, with a number of routes to cover. Whitewater Lake has 4 routes on the east side of the lake, 3 on the west side and one stationary route. Oak Lake has 5 routes, 2 of which are stationary. Oak Hammock Marsh has 3 routes, although one was not assessable this year due to high water levels. Finally, the North, East and West Shoal Lakes has 4 routes. Each route at each location is normally monitored three times in the spring. While all species observed should be recorded under ISS protocol lists, only shorebirds are included in the data. Some surveys that were completed for ISS did not contain any shorebird sightings, so while a site may have been monitored a number of times, the surveys with actual shorebird sightings may be less. All four locations are summarized below:

Oak Hammock Marsh

Species	Total # of Individuals	Proportion (%) of Individuals
Killdeer	2	3
Marbled Godwit	6	10
Willet	8	12.90
Wilson’s Phalarope	46	74.19
Total	62	100
Total # of Species	4

The results from Oak hammock Marsh show us the contrast between this spring and last spring. This year, only four species were identified during the ISS period. The number of individuals amongst those species is also much lower than spring 2021.

Route 1 and Route 2 were surveyed once during this period and the shorebird scrape was monitored twice. Route 3, the Teal Dike, became flooded and collapsed so it was not assessable to monitor. Overall the high water levels would most likely have affected the habitat for shorebirds, thus the lower numbers.

West, East and North Shoal Lakes

Species	Total # of Individuals	Proportion (%) of Individuals
American Avocet	12	22
Greater Yellowlegs	2	4
Killdeer	13	24
Shorebird sp.	4	7
Lesser Yellowlegs	1	2
Marbled Godwit	5	9
Spotted Sandpiper	1	1.82
Whimbrel	6	10.91
Willet	7	12.73
Wilson’s Phalarope	4	7.27
Total	55	100
Total # of Species	10

Shoal Lakes was surveyed 14 times over the spring ISS period. It is important to note that multiple routes can be surveyed on one day. Route 1 was surveyed five times, route 2 was surveyed twice, route 3 was surveyed once, route 4 was surveyed five times and the stationary “Campground” point was surveyed three times.

Oak/Plum Lakes

Species	Total # of Individuals	Proportion (%) of Individuals
American Avocet	2	3
Killdeer	17	23
Least Sandpiper	1	1
Marbled Godwit	4	5
Pectoral Sandpiper	1	1
Spotted Sandpiper	10	13.33
Willet	9	12
Wilson’s Phalarope	30	40
Wilson’s Snipe	1	1.33
Total	75	100
Total # of Species	9

Oak Lake has rive shorebird routes, including two that are stationary (route 3 and 5). Of these routes, route 1 was surveyed twice, route 2 was surveyed twice, route 3 and route 4 were surveyed once. Flooding over a low spot in the access road meant that Route 5 (a small wetland), was not able to be surveyed. In total, volunteers visited the IBA to surveyed six times.

Whitewater Lake

Species	Total # of Individuals	Proportion (%) of Individuals
American Avocet	33	3
Baird’s Sandpiper	37	4
Dunlin	6	1
Greater Yellowlegs	1	0
Hudsonian Godwit	15	2
Killdeer	14	1.47
Least Sandpiper	3	0.31
Lesser Yellowlegs	23	2.41
Marbled Godwit	5	0.52
Pectoral Sandpiper	15	1.57
Peep sp.	66	6.92
Red Necked Phalarope	315	33.02
Ruddy Turnstone	3	0.31
Sanderling	4	0.42
Semipalmated Sandpiper	166	17.40
Shorebird sp.	10	1.05
Short-billed Dowitcher	1	0.10
Spotted Sandpiper	3	0.31
White-rumped Sandpiper	176	18.45
Stilt Sandpiper	7	0.73
Willet	15	1.57
Wilson’s Phalarope	35	3.67
Wilson’s Snipe	1	0.10
Total	954	100
Total # of Species	23

Whitewater Lake was visited by volunteers to survey 14 times in total. Sexton’s point, the only stationary route, was surveyed three times. On the west side of the Lake, route W1 was surveyed three times, route W2 was surveyed six times and route W3 was surveyed twice. On the east side of the lake, each route was monitored once due to wet conditions and dirt roads.

Based on these summaries, it is clear that the wet weather Manitoba has experienced this spring affected the ISS monitoring season. All four IBAs showed numbers inconsistent with previous years and there was much less variety in the shorebird species observed. Like last year, Whitewater Lake had the highest counts for shorebirds of the four IBAs but the number was greatly reduced. We have several hypothesis as to why this might be, but of course we do not know for certain. Perhaps it is possible that migratory shorebirds were simply staying in areas where it was less wet, possibly areas across the border in Saskatchewan, as the IBAs all had much higher water levels that the previous year. Or if the shorebirds were in Manitoba, perhaps they were spread over the higher-than-normal number of ephemeral (temporary) wetlands spread across the landscape this year, instead of clustering at our usual shorebird “hotspots”. If weather is indeed influencing numbers of shorebirds, It will be interesting to see what the Fall ISS period brings, and then next spring.

Another thing to consider is volunteer “effort”. Of course our volunteers put in a lot of effort to go out and count shorebirds, but effort also has a meaning scientifically as well. Ideally when comparing between years we want to amount of effort to be standardized as much as possible. For example, going out to survey for 5 hours on three different mornings (15 hours of “effort”) will likely net you more birds than surveying for five hours on one morning (5 hours of “effort”). Our big disruptor of effort this year was the residual snow late into the spring, wet road conditions (on dirt roads), and/or collapsed dikes. While trying to survey each route three times in the spring is important, volunteer safety and safe route access is more important.

Once again, summaries like this are possible because of the time and effort of volunteers, so thank you to everyone who went out and monitored this spring! A big thank you to Glennis Lewis, Tim Poole and Ansley Woods for surveying at Oak Lake; Gillian Richards for surveying at Oak Lake and Whitewater Lake, Duane Diehl and Tom and Renee Will for surveying at Whitewater Lake; Bonnie Chartier, Mike Karakas, Tami Reynolds for surveying at Oak Hammock Marsh and the Shoal Lakes; and Jo Swartz and Jan Bradley for surveying at the Shoal Lakes.

If you are interested in volunteering for our fall International Shorebird Surveys, we are looking for volunteers! Believe it or not, we are already in the fall ISS survey period, which runs until October 25th, 2022. Email iba@naturemanitoba.ca for more information.

-Ariel