Cattle Egret

HÉRON GARDE-BOEUFS

Bubulcus ibis (Linnaeus)

 

Rare visitor.

 

Less aquatic in its habits than most herons, the Cattle Egret is most often found in pastures, where it feeds on grasshoppers and other invertebrates that are stirred up by cattle and horses. This species’ stocky proportions are distinctive in all plumages, and the yellow to orange bill separates it from all but the much larger Great Egret. Adults are also distinguished from other egrets by the rusty accents to their white breeding plumage.

 

Among the most surprising birds on the long list of rare sightings at Churchill are lone Cattle Egrets in late October 1989 and on 15 October 2001. Though these individuals were more likely windblown strays than over-ambitious pioneers, the species has extended its global range dramatically in the last century or so. Originally an Old World species, it is thought to have crossed the Atlantic from Africa to South America around 1880. From there, the species reached the United States in the early 1940s, and its subsequent spread through North America is one of the best documented avian phenomena of the 20th century.^1,2 Equally dramatic range extensions have occurred in Eurasia and Australia.

 

The Cattle Egret was first seen in Canada in 1952, but it has not become established as a regular breeding species. Nesting has occurred sporadically in southern Ontario since 1962, in Minnesota since 1971, and once in Saskatchewan in 1981.^3-5 David Plews and John Lane found Manitoba’s first Cattle Egret between Alexander and Griswold on 27 May 1961.⁶ Other observations followed in 1967, 1971, and nearly every year since then for a total exceeding 70 records. During the second half of the 1970s the species appeared to have become a regular spring and summer visitor, with as many as 31 being seen in one flock at Oak Hammock Marsh in early September 1978.^7,8 After 1979, however, the frequency of reports decreased sharply, and comparable numbers were not seen again for 20 years. A concentration of Cattle Egrets at Whitewater Lake peaked at 47 birds on 6 September 1999, and a similar-sized flock appeared there in August 2002. Forty small egrets near Langruth on 1 September 1999 were also almost certainly this species.

 

With one exception, Manitoba records extend from 3 May to 2 November, with the majority in May and between August and October. An extraordinarily late bird lingered at a cattle feedlot near Cypress River until early December 2000. Most observations have occurred in the prairie region, especially at Oak Hammock Marsh and Whitewater Lake; outlying localities include Bissett, Gypsumville, and Hecla Island, as well as Churchill.

 

¹ Palmer 1962; ² Larson 1982; ³ Godfrey 1986; ⁴ Janssen 1987; ⁵ Roney 1982; ⁶ Plews 1961; ⁷ K. Gardner, WW 16 Sept. 1978; ⁸ Gardner 1981.

 

R.F. Koes