The White-faced Ibis is now a well-established breeder in Alberta. The species' breeding range has spread beyond the initial breeding colonies established in the 1970s (Pakowki Lake, Frank Lake) to other colonies in other large bodies of water (such as Third Lake) and even in smaller sloughs (we observed a small colony this summer of at least 30 individuals in a small 15-acre slough east of Airdrie in 2015, and a flock of 65 in 2017). Ibis are becoming a regular sight in lakes and sloughs in southern Alberta during the breeding season; indeed, apart from avocet, yellowlegs, and dowitchers, we probably saw more ibis this year than any of the other large shore and wading birds, particularly after the young had dispersed from their nests.
The question remains, of course, why are they here, and what happened in the last 40 years or so to bring them here? Shaffer et al. (2007) in their paper discussing the range expansion of ibis into North Dakota suggested a number of possible factors, including fluctuations in southern ibis populations, habitat change and loss in other parts of the ibis' range (due in part to pesticide use), climate and precipitation patterns in northern portions of the range (specifically, an increase in precipitation), and human factors (for example, people moved out of rural areas of North Dakota following the droughts in the 1930s, and moved from livestock operations towards small grain production, thereby lessening pressures on wetlands). In short, the conditions in the northern prairie and parkland regions became more attractive to ibis than those in the southern ranges.
Similar push and pull factors may well have contributed to the introduction of breeding populations of other species, such as Black-necked Stilt, in Alberta. It is interesting to speculate what species may come next; Glossy Ibis have been reported in North Dakota, Idaho, and Manitoba - will they appear here soon? UPDATE: On May 29, 2017, Ken Orich identified a Glossy Ibis while participating in the Milk River/Writing-on-Stone Bird Count. I guess I nailed that one! (Thanks to Bob Parsons for reminding me to update this blog).