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POPULATIONS Introduction There have been many changes to Ontario bird populations since the pub- lication of the first issue of Ontario Birds in 1983. Some of these, such as the dra- matic increase in Wild Turkey (Meleagris gallopavo) across southern and central Ontario, are evident to most observers, while others, such as the near extirpation of the Henslow’s Sparrow (Ammodramus Changes in henslowii) have slipped by largely unno- ticed by any but the most involved or Ontario bird informed. In this article, through a series of 11 brief summaries by Ontario experts, populations: an overview is provided of some of the major changes that have taken place to 1983-2016 individual species and groups of birds Michael D. Cadman, Andrew R. Couturier, over the past three decades. The goal is Jon D. McCracken, Donald A. Sutherland, not to provide a comprehensive analysis Kenneth F. Abraham, Lyle E. Friesen, of bird population change, but to high- Christian A. Friis, Kevin C. Hannah, light certain species and/or groups that Shawn W. Meyer, David J. Moore, will help provide insight into changes of Mark K. Peck, Douglas C. Tozer interest to readers of Ontario Birds. To and D.V. Chip Weseloh better understand the information pro- vided here, and for a broader perspective on how Ontario’s birds are faring relative to those across the country and the con- tinent, we highly recommend two recent publications: The State of Canada's Birds (NABCI-Canada 2012) and The State of North America's Birds (NABCI 2016). The State of Canada's Birds (NABCI- Canada 2012) found that, on average, Canadian breeding bird populations have decreased 12% since 1983, when effec- tive monitoring began for most species. For species with sufficient data to moni- tor their status, 44% have decreased, 33% have increased and 23% have shown Wild Turkey. Photo: Daniel Cadieux 68 Ontario Birds August 2016 little overall change. Some groups, such fate of migratory birds is intertwined as grassland birds, aerial insectivores and with that of resident species and habitats shorebirds, show substantial declines. outside of the province. A full lifecycle Other groups such as waterfowl, raptors approach, addressing species' needs dur- and colonial waterbirds are increasing, ing breeding, migration and wintering, due to careful management, changes in is essential for conserving Ontario's (and habitat and reductions in environmental Canada's) birds. contaminants (NABCI-Canada 2012). The 25 species that have increased The situation at the continental scale and decreased the most in Ontario since provides additional cause for concern. 1983 according to the Breeding Bird The State of North America's Birds Survey (BBS) are shown in Table 1. The (NABCI 2016) — an unprecedented BBS is a road-side survey, so it represents vulnerability assessment of our conti- terrestrial landbirds better than wetland nent's birds, including Canada, the Unit- and colonial species, and can only pro- ed States and Mexico — concludes that vide trends for areas with roads. As a 432 of North America's 1,154 native result, some significant changes in num- bird species (37%) require urgent con- bers, such as those of the Trumpeter servation action. In particular, birds that Swan (Cygnus buccinator) are not shown depend on oceans and tropical forests are in this table, and there is no coverage for most imperiled due to severe habitat vast areas of northern Ontario’s boreal threats, restricted ranges and declining forest and Hudson Bay Lowlands. Note populations. Species that rely on coasts, also that some terrestrial species, such as grasslands and arid lands are faring poor- the Northern Bobwhite (Colinus vir- ly on average, while results for temperate ginianus) and Yellow-breasted Chat (Icte- forests, tundra, wetlands and the boreal ria virens) do not appear on the table, forest are mixed. despite their near extirpation from the Familiar Ontario bird species can be province over the past 30 years, because found among the list of winners and los- they are encountered so infrequently that ers at both the national and continental BBS does not track them reliably. Some scales. Interestingly, the 22% of Canada’s of the patterns revealed in the table, such bird species that stay primarily year- as the large increases in many “big” birds, round in Canada are doing very well gen- the expansion of species edging north- erally, with an overall increase of 50% ward into and within the province, and since 1970. But the 15% that winter in the decline of the grassland and aerial South America have declined by 60% in insectivore species are expanded on in the Canada in the same period (NABCI- accounts that follow. Canada 2012). The reasons for this pat- tern are unknown, but it suggests that significant changes are underway either in the wintering areas, along migratory routes or both, and it is evident that the Volume 34 Number 2 69 POPULATIONS Table 1. The 25 species showing (a) the largest increases and (b) the largest decreases in Ontario in the period 1983-2013 according to the Breeding Bird Survey (Sauer et al. 2014). Nomenclature follows American Ornithologists’ Union (2015). Trend shown is annual % change. a) Largest Increases 1983-2013 b) Largest Decreases 1983-2013 Rank Species Trend Rank Species Trend 1 Wild Turkey 31.4 1 Loggerhead Shrike -11.0 2 Canada Goose 18.1 2 Chimney Swift -7.8 3 Double-crested Cormorant 18.0 3 Cliff Swallow -7.4 4 Sandhill Crane 16.5 4 Common Gallinule -6.7 5 Bald Eagle 14.5 5 Bank Swallow -6.3 6 House Finch 13.8 6 Evening Grosbeak -6.1 7 Red-bellied Woodpecker 11.6 7 Rusty Blackbird -5.9 8 Turkey Vulture 8.9 8 Black Tern -5.7 9 Palm Warbler 7.7 9 Blue-winged Teal -4.9 10 Northern Parula 7.3 10 Purple Martin -4.7 11 Blue-winged Warbler 7.2 11 Western Meadowlark -4.5 12 Orchard Oriole 5.1 12 House Sparrow -4.3 13 Osprey 4.8 13 Ring-necked Pheasant -4.2 14 Philadelphia Vireo 4.7 14 Herring Gull -3.8 15 Wood Duck 4.6 15 Tennessee Warbler -3.7 16 Blue-headed Vireo 4.4 16 Tree Swallow -3.7 17 Hooded Merganser 4.2 17 Red-headed Woodpecker -3.7 18 Pine Warbler 3.8 18 Brown-headed Cowbird -3.7 19 Cooper's Hawk 3.7 19 Killdeer -3.6 20 Brown Creeper 3.6 20 Bobolink -3.5 21 Yellow-bellied Flycatcher 3.5 21 Spotted Sandpiper -3.5 22 Ring-billed Gull 3.5 22 Vesper Sparrow -3.5 23 Merlin 3.5 23 American Black Duck -3.3 24 Northern Cardinal 3.2 24 Upland Sandpiper -3.2 25 Mallard 2.8 25 Eastern Whip-poor-will -3.0 70 Ontario Birds August 2016 Greater Snow Geese. Photo: Brian Morin SpeciesAccounts Ontario’s Goose Populations cereal grains left after harvesting, and The story of geese in Ontario since the green forage plants in managed rural and first issue of Ontario Birds is one of an urban grasslands. For temperate breeding overall dramatic and positive response to Canada Geese (Branta canadensis maxi- human-caused landscape changes. ma), this adaptation extends to all sea- Changes both within and beyond On - sons as they also nest and rear young in tario have resulted in more geese almost agricultural and urban areas. Secondary everywhere. The main cause is that the causes of population increases include geese adopted new diets in the mid to lower harvest rates/higher survival rates late 20th century by foraging in agricul- for Canada, Cackling (B. hutchinsii), turally dominated habitats. With a single Lesser Snow (Chen caerulescens caerul - exception among regularly occurring escens) and Greater Snow Geese (C. c. species, diets of geese during migration atlantica), a reflection of changing demo- and winter now consist primarily of graphics among hunter populations. Volume 34 Number 2 71 POPULATIONS Canada Geese in Ontario include 300,000 birds in the mid 1980s to 1.4 temperate breeders of the south and near million in 2009. north, and subarctic breeders of the In similar fashion, the Ross’s Goose Hudson Bay Lowlands (HBL). Temper- (C. rossii) has increased as both a migrant ate breeders increased from about 10,000 and a breeder in Ontario. A noteworthy to 180,000 breeding adults from 1980 to rarity in 1982, it was removed from the 2006, but have since declined somewhat review list of the Ontario Bird Records (CWSWC 2015). Subarctic breeders Committee (OBRC) for southern increased throughout the mid 20th cen- Ontario in 2006 (Crins 2007). The tury to the late 1980s, to over 900,000 number of breeders in the Ontario HBL birds, but have declined gradually since was estima ted to be a few hundred pairs then and have been relatively stable for as of 2005 (Abraham 2007b), but has the past decade at about 400,000 breed- likely increased since then. Its Ontario ing adults (CWSWC 2015). status reflects an increase from about The Cackling Goose became recog- only 6,000 birds continentally in the nized as a separate species from Canada 1940s to over 2.7 million in 2014 and a Goose in 2004 (Banks et al. 2004). large-scale east ward range expansion Ontario-observed Cackling Geese come (CWSWC 2015). from the Baffin Island breeding segment In Ontario, the pattern of increased of the Mid-Continent Population (Abra- observations of migrating White-front- ham 2005), which grew from about 1 ed Geese (Anser albifrons) mimics the million in 1987 to almost 4 million in Ross’s Goose story. The Mid-Continent 2013 (CWSWC 2015).