The Great Lakes Decadal Colonial Waterbird Census (GLDCWC) is best suited to colonial species like Great Egret, samples most of the Canadian breeding range, and has high precision in its trends. However, the GLDCWC has only been undertaken four times over 50 years. GLDCWC data indicate a large long-term increase in abundance since the early 1970s, with increases in both documented nest numbers and colonies. The Breeding Bird Survey (BBS) provides annual data since 1970, but has more limited coverage and its precision is low because of high uncertainty around estimates in the early years. BBS trends from the United States have higher reliability and likewise show a large increase in abundance. The Ontario Breeding Bird Atlas also reflects a large increase between the first atlas in the early 1980s and the second in the early 2000s.

The goal for Great Egret is to remain at or above its recent population level, based on the Breeding Bird Survey. Trend data show that Great Egret is currently within its goal range.