Survey 3: Report

Survey 3 of the Dundas IBA (ON005): Report

The third Dundas IBA Bird Survey was conducted on May 11, 2019. The weather was very cooperative, and while the temperature only reached a high of 12°C, the winds were calm and sun was shining in the morning, followed by an overcast afternoon and evening.

This survey, which can also be more lengthily referred to as a “Dundas Valley & Dundas Marsh Important Bird & Biodiversity Area (IBA) Survey” was conducted exclusively within natural lands found inside the boundary of the IBA, which in short covers the Dundas Valley from Summit Muskeg through to Spencer Creek into Cootes Paradise, extending to Burlington Heights.

To read more about this IBA, see

For those familiar with the Christmas Bird Counts, this survey followed a similar methodology, but did not include urban areas or backyard birdfeeders. Lists are submitted and compiled via eBird.

In this first cycle of counts going from 2018 through 2022, we aim to have one complete survey per calendar month, for a total of 12 surveys. These are normally scheduled in a 5-month stagger, but our planned April count posed dangerous weather (all day wind & rain, 0°C high) so we decided to postpone and have our May survey this year. In 2021, we will substitute our originally scheduled May count as an April one instead to make up for this.

This count included 9 core volunteer counters who impressively covered an immense area with small numbers. No doubt peak birding season is hard to schedule an assigned count for, but nonetheless we covered the most important zones, resulting in a total of 21 checklists.

A total of 3388 birds were counted, with 128 species (plus 5 other taxa) identified in the 21 zones.

Of the six “criteria species” (species that have at one time been present in significant numbers within the IBA) that occur within the spring season, only one was observed — the Chimney Swift (19). This is not very surprising as those species on the list are a mix of very rare and hard-to-find species, and some may not have arrived yet on breeding territory.

Our top-twelve species for Survey 3 were: Red-winged Blackbird (451), Blue Jay (238), Tree Swallow (137), Yellow Warbler (124), American Goldfinch (106), Song Sparrow (104), American Robin (102), Baltimore Oriole (101), Barn Swallow (98), Canada Goose (96), Common Grackle (86), Black-capped Chickadee (85). The only repeat species from the top twelve of both previous surveys are American Robin and Black-capped Chickadee.
There were 6 species with greater than 80% distribution for reported zones: Song Sparrow (95%), American Robin (86%), Blue Jay (81%), American Goldfinch (81%), Northern Cardinal (81%).

A total of 69 species were seen in only 20% or fewer lists, which is understandable considering this is a survey during peak migration for a large number of species.

Of those, 32 species were highly localized, only occurring on one checklist: Trumpeter Swan, Gadwall, Greater Scaup, Common Merganser, Ruddy Duck, Common Nighthawk, Ruby-throated Hummingbird, American Bittern, Great Egret, Broad-winged Hawk, Eastern Screech-Owl, Great Horned Owl, Yellow-bellied Sapsucker, American Kestrel, Yellow-throated Vireo, Red-eyed Vireo, Horned Lark, Purple Martin, Bank Swallow, Brown Creeper, Purple Finch, Vesper Sparrow, Lincoln’s Sparrow, Bobolink, Eastern Meadowlark, Orchard Oriole, Rusty Blackbird, Hooded Warbler, Cape May Warbler, Blackburnian Warbler, Canada Warbler, Scarlet Tanager.

There are 38 species that have occurred in all three surveys so far, with 20 of them occurring with a double-digit minimum on every count, marking them as fairly reliable spring/summer/fall species for the Dundas IBA: Canada Goose, Mallard, Rock Pigeon,Mourning Dove, Ring-billed Gull, Herring Gull, Great Blue Heron, Red-bellied Woodpecker, Downy Woodpecker, Hairy Woodpecker, Blue Jay, American Crow, Black-capped Chickadee, White-breasted Nuthatch, Carolina Wren, American Robin, European Starling, Cedar Waxwing, American Goldfinch, Northern Cardinal. When we do our first winter survey next February, this may whittle down a bit.

Some highlights of the survey include:

Our first and only American Bittern of any survey was observed in Cootes Paradise waterways.

An early and evidently very hungry solo Common Nighthawk was found and photographed mid-day catching insects at Slote Marsh.

On survey day Cootes Paradise was host to a minimum of 7 Bald Eagles — counters did count a combined total of 12 within close proximity at different times of day so we’re adjusting to highest counted by one counter to prevent overlaps.

A lone Yellow-bellied Sapsucker was observed at Rock Chapel, likely a late migrant.

An American Kestrel was spotted at Iroquoia Heights Conservation Area.

The Cootes Paradise waterways also revealed a Yellow-throated Vireo, and Hooded Warbler.

Pine Siskin has still not missed a single survey, with 3 observed total this time, split between Dundas Valley CA and Crooks’ Hollow CA.

Marsh Wren made themselves known in large numbers in the Cootes Paradise Waterways (9) and one very territorial male seen and heard singing and scolding at Slote Marsh.

A new warbler migration hotspot was discovered during this survey: Crooks Hollow Conservation Area. The removal of a dam in Spencer Creek there has sped up the waterway considerably, and now has an abundance of insects which has attracted warblers, swallows, and other insectivores in large numbers.

In total, 21 species of warbler were observed, 15 of which were present at Crooks Hollow.

This is the first survey where we have also made use of bioacoustic monitors at two sites, courtesy of the Hamilton Bioacoustics Research Project with the Hamilton Naturalists’ Club. So far only nocturnal recordings have been scanned for additional species. (These species will be noted separately in our count data.)

Both sites with bioacoustic monitors observed American Woodcock in breeding display, a species not observed by any human counters. A monitor at Cartwright Nature Sanctuary also captured migration flyovers of Long-tailed Duck and a possible lone Upland Sandpiper. Both sites heard nocturnal flyovers of Spotted Sandpiper, though these were also counted by our volunteers on the day. Any further findings from the daytime recordings will be appended to this report on the Hamilton Naturalists’ Club website.

Due to the limited number of volunteers spread over such a large area, volunteers were not asked to specify breeding status of observed species, though this may be done in future surveys when both migratory and locally breeding species are expected in a count.

Thank you to all whom have assisted in this third survey, including the RBG and HCA for their assistance.

Special thanks also to the RBG’s “Not Just A Birding Club” which had 27 participants contributing to one checklist.

Our fourth survey will be held September, likely a couple weekends before the OFO Convention to give some breathing space to any volunteers who may be attending that.

Feel free to contact me with any questions you may have.

Rob Porter
Compiler, Dundas IBA Survey 3


IBA Criteria Species for Spring

Observed in Survey 3:
Chimney Swift
Not found in Survey 3:
Acadian Flycatcher
Little Gull
Loggerhead Shrike
Prothonotary Warbler
Yellow-breasted Chat

Survey 3 Count Totals

Each line follows the format: species name, count, distribution (% of checklists present within)

e.g. Sandhill Crane 4   (10%): Four Sandhill Cranes, observed at 10% of reported zones

List is in taxonomic order.

* Denotes species adjusted lower to account for possible observation overlaps.

Canada Goose    96  (48%)
Mute Swan   14  (19%)
Trumpeter Swan  2   (5%)
Wood Duck   19  (14%)
Gadwall 2   (5%)
Mallard 37  (33%)
Greater Scaup   1   (5%)
Common Merganser    1   (5%)
Ruddy Duck  1   (5%)
duck sp.    20  (5%)
Wild Turkey 4   (10%)
Rock Pigeon 18  (10%)
Mourning Dove   27  (52%)
Common Nighthawk    1   (5%)
Chimney Swift   19  (19%)
Ruby-throated Hummingbird   2   (5%)
Sora    5   (14%)
Sandhill Crane  4   (10%)
Killdeer    3   (10%)
Spotted Sandpiper   7   (19%)
Ring-billed Gull    23  (43%)
Herring Gull    14  (29%)
Caspian Tern    16  (29%)
Common Tern 11  (14%)
Double-crested Cormorant    68  (43%)
American Bittern    1   (5%)
Great Blue Heron    20  (29%)
Great Egret 2   (5%)
Turkey Vulture  32  (57%)
Osprey  2   (10%)
Sharp-shinned Hawk  3   (14%)
Accipiter sp.   1   (5%)
* Bald Eagle    7   (14%)
Broad-winged Hawk   1   (5%)
Red-tailed Hawk 10  (29%)
Eastern Screech-Owl 1   (5%)
Great Horned Owl    1   (5%)
Belted Kingfisher   8   (24%)
Yellow-bellied Sapsucker    1   (5%)
Red-bellied Woodpecker  38  (71%)
Downy Woodpecker    21  (62%)
Hairy Woodpecker    11  (29%)
Pileated Woodpecker 3   (14%)
Northern Flicker    25  (62%)
American Kestrel    1   (5%)
Least Flycatcher    9   (29%)
Eastern Phoebe  6   (24%)
Great Crested Flycatcher    11  (33%)
Eastern Kingbird    9   (33%)
Yellow-throated Vireo   1   (5%)
Blue-headed Vireo   22  (48%)
Warbling Vireo  16  (29%)
Red-eyed Vireo  1   (5%)
vireo sp.   1   (5%)
Blue Jay    238 (81%)
American Crow   48  (62%)
Horned Lark 4   (5%)
Northern Rough-winged Swallow   20  (24%)
Purple Martin   1   (5%)
Tree Swallow    137 (67%)
Bank Swallow    4   (5%)
Barn Swallow    98  (48%)
Cliff Swallow   18  (14%)
swallow sp. 20  (5%)
Black-capped Chickadee  85  (67%)
Red-breasted Nuthatch   9   (24%)
White-breasted Nuthatch 23  (43%)
Brown Creeper   2   (5%)
House Wren  35  (62%)
Winter Wren 2   (10%)
Marsh Wren  10  (10%)
Carolina Wren   29  (52%)
Blue-gray Gnatcatcher   24  (38%)
Ruby-crowned Kinglet    33  (48%)
Eastern Bluebird    8   (19%)
Veery   4   (10%)
Swainson's Thrush   4   (14%)
Hermit Thrush   4   (14%)
Wood Thrush 3   (10%)
American Robin  102 (86%)
Gray Catbird    64  (76%)
Brown Thrasher  2   (10%)
European Starling   51  (33%)
Cedar Waxwing   19  (19%)
House Finch 9   (10%)
Purple Finch    1   (5%)
Pine Siskin 3   (10%)
American Goldfinch  106 (81%)
Chipping Sparrow    21  (43%)
Field Sparrow   30  (24%)
White-crowned Sparrow   3   (10%)
White-throated Sparrow  26  (43%)
Vesper Sparrow  2   (5%)
Savannah Sparrow    9   (10%)
Song Sparrow    104 (95%)
Lincoln's Sparrow   2   (5%)
Swamp Sparrow   18  (24%)
Eastern Towhee  12  (24%)
Bobolink    2   (5%)
Eastern Meadowlark  2   (5%)
Orchard Oriole  5   (5%)
Baltimore Oriole    101 (76%)
Red-winged Blackbird    451 (86%)
Brown-headed Cowbird    39  (57%)
Rusty Blackbird 1   (5%)
Common Grackle  86  (52%)
Ovenbird    9   (29%)
Northern Waterthrush    3   (14%)
Blue-winged Warbler 9   (19%)
Black-and-white Warbler 26  (52%)
Nashville Warbler   15  (33%)
Common Yellowthroat 22  (33%)
Hooded Warbler  1   (5%)
American Redstart   18  (43%)
Cape May Warbler    1   (5%)
Northern Parula 10  (10%)
Magnolia Warbler    6   (10%)
Bay-breasted Warbler    4   (10%)
Blackburnian Warbler    5   (5%)
Yellow Warbler  124 (62%)
Chestnut-sided Warbler  6   (24%)
Black-throated Blue Warbler 26  (38%)
Palm Warbler    45  (33%)
Pine Warbler    9   (19%)
Yellow-rumped Warbler   61  (43%)
Black-throated Green Warbler    13  (33%)
Canada Warbler  1   (5%)
warbler sp. (Parulidae sp.) 13  (5%)
Scarlet Tanager 2   (5%)
Northern Cardinal   74  (81%)
Rose-breasted Grosbeak  42  (67%)
Indigo Bunting  3   (10%)
House Sparrow   26  (29%)

TOTAL birds counted 3388
Species counted 128
Other taxa counted (spuh, slash, or hybrid) 5

Additional Species from Bioacoustics Monitors (2 sites)

Only nocturnal recordings have been accounted for at the time of this report. Only species not observed by volunteers are listed here.

American Woodcock (2 sites)
Long-tailed Duck (1 site)
Upland Sandpiper (1 site, unconfirmed)