The cuckoo family has two representatives which breed in Ontario, the black-billed and less-abundant yellow-billed species. The latter may be just as abundant on a continent-wide basis, but occupies a more southerly range, overlapping with that of its cousin. Below is a juvenile black-billed cuckoo, the only species seen in the Township in our explorations. This obliging individual ate a large caterpillar and then rested on a low branch, enabling these photographs to record an unusual sighting in the esker just west of Campbellford, on 18 August 2014. Cuckoos are "low-key" birds here, probably in part because their summer visits are largely taken up with ensuring the next generation of cuckoos (?). The two seasonal visiting species are also less flamboyant than the cuckoos seen elsewhere (e.g., Cuba) and their calls are less obvious than the signature "cuck-oo" of the European species, that many think is synonymous with the arrival of spring in rural England. The British cuckoo is one of the various birds mentioned in Shakespeare (Goodfellow and Hayman, 1983).
The period of observations included just one other sighting elsewhere, at the Don Valley brickyard site in Toronto. The three local observations were in heavily wooded areas near the Trent river and in the esker near Trout Creek. The earliest was on 13 June and the latest on 18 August.
Cuckoo numbers fluctuate depending on cyclic populations of prey species such as tent caterpillars. At Presqu'ile park, the black-billed cuckoo is an uncommon migrant and summer resident. The bird has been seen in the park as early as 16 May - an observation by Fred Helleiner - and as late as 22 September, noted by Doug McRae (LaForest, 1993, pp.205-206). In the Kawarthas, the bird has been noted between 23 April and 01 October (Sadler, 1983, pp.92-93). Across Ontario, the black-billed cuckoo is found mainly in the southern half of the province, and is often overlooked due to a retiring nature, hiding in thickets (Cadman et al., 1987, pp.198-201). Highest abundances for the species are in the North Bay- Sudbury- Manitoulin Island region, and eastwards in pockets from Georgian Bay to Ottawa along the southern margin of the Canadian shield (Cadman et al., 2007, pp.284-287).
The black-billed cuckoo is capable of building a perfectly good nest and raising its young, though its occasional tendency to act as a brood parasite is well-known. Its victims are often smaller birds such as chipping sparrows and yellow warblers (e.g., Bent, 1940, pp.70-84). Over 80 species (1%) of birds are interspecific brood parasites, thus our cuckoo is less of an anomaly than one might suppose (Gadagkar and Kolatkar, 1996). The north American black-billed and yellow-billed cuckoos commonly nest for themselves, and so the smaller cowbird is certainly a bigger threat to small nesting birds in our area.
The majority of the 125 or 127 species of cuckoo are tree-dwelling. Most are strong fliers, and may migrate long distances (Gooders, 1975, pp.182-185; Whitfield, 1988, pp.78-81). Cuckoos are adept at eating some pests, including the periodic plagues of tent caterpillars (e.g., Whelan, 1993, 1996). Indeed, "an abundance of caterpillars in a locality is very likely to bring with it an invasion of cuckoos", as noted in Alberta in 1923-1925 (Bent, 1940, p.77).
Bent,AC (1940) Life Histories of North American Cuckoos, Goatsuckers, Hummingbirds, and their Allies. Dover Publications, Inc., reprint of Smithsonian Institution Bull. 176, in 2 volumes in 1964 / as 1 volume in 1989, 506pp.
Cadman,MD, Eagles,PFJ and Helleiner,FM (1987) Atlas of the Breeding Birds of Ontario. Federation of Ontario Naturalists and Long Point Bird Observatory, published by University of Waterloo Press, 617pp.
Cadman,MD, Sutherland,DA, Beck,GG, Lepage,D and Couturier,AR (editors) (2007) Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada,Environment Canada,Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, 706pp.
Gadagkar,R and Kolatkar,M (1996) Evidence for avian mafia! Current Science 70 no.2, 115-117, 25 January.
Gooders,J (1975) Birds: an Illustrated Survey of the Bird Families of the World. Hamlyn, London, 353pp.
Goodfellow,P and Hayman,P (1983) Shakespeare's Birds. Penguin Books Ltd, 96pp.
LaForest,SM (1993) Birds of Presqu'ile Provincial Park. Friends of Presqu'ile Park / Ontario Ministry of Natural Resources, 436pp.
Sadler,D (1983) Our Heritage of Birds: Peterborough County in the Kawarthas. Peterborough Field Naturalists / Orchid Press, Peterborough, ON, 192pp.
Whelan,P (1993) A banquet of tent caterpillars. Globe and Mail, 26 June.
Whelan,P (1996) Sensations of hawk owls. Globe and Mail, 03 August.
Whitfield,P (editor) (1988) The Macmillan Illustrated Encyclopedia of Birds. Collier Books, Macmillan Publishing Company, New York, 224pp.