From Waterbirds in the USA:
Comparisons of Reddish Egret (Egretta rufescens) Diet During the Breeding Season Across its Geographic Range
Although the prey of Reddish Egrets (Egretta rufescens) generally consists of shallow-water, euryhaline fish species, rangewide differences in breeding season diet have not been examined. Furthermore, the relative proportions of the two Reddish Egret color morphs vary from east to west across the species’ range. Color morph may influence foraging efficiency, but variations in prey across the species’ range and between morphs is undocumented.
By examining boluses from Reddish Egret (n = 109) nestlings, prey species proportions were compared between morphs, among regions and among colonies within Texas. Between regions, prey species and proportion of species differed widely; however, fish species with similar life histories were selected across the Reddish Egret’s range (Bahamas: 100% sheepshead minnow (Cyprinodon variegatus); Texas: 85% sheepshead minnow; Baja California Sur: 49% American shadow goby (Quietula y-cauda); Yucatán: 64% Yucatán pupfish (C. artifrons).
Within the Laguna Madre in Texas, significant differences in prey species were not detected between morphs (F(1,61) = 1.36, P = 0.224); however, prey mass by species differed between colonies (F(1,60) = 2.68, P = 0.010). While our results only pertain to Reddish Egret diet during the breeding season, this study increases our understanding of Reddish Egret ecology and provides initial diet information across the species’ range.