An investigation of the insect component of the diet of the Grey Heron Ardea cinerea and the Little Egret Egretta garzetta

Capsule: Aquatic insects make up a relatively small part of the Grey Heron diet, while Little Egrets consume numerous beetles, both aquatic and terrestrial.
Aims: To explore the extent of insect predation by Grey Herons and Little Egrets. Regurgitated pellets were collected from beneath trees in which herons and egrets were nesting. 70 Grey Heron and 48 Little Egret pellets were collected from the RSPB reserve at Northward Hill, Kent. These pellets were disaggregated, and prey items collected and sorted under a binocular microscope.
Results: Grey Herons were found to feed on a relatively small number of aquatic beetles (Coleoptera) (7 species, 32 individuals) and bugs (Hemiptera) (2 species, 6 individuals). Little Egrets, in contrast, fed on a diverse array of beetle species, both aquatic (3 families, 11 species, 48 individuals)) and terrestrial (10 families, 35 species, 111 individuals), and on a few aquatic bugs (1 family, 1 species, 3 individuals). The extent of predation on terrestrial beetles constitutes new information on the diet of Little Egrets.
Conclusion: Insects, both terrestrial and aquatic, represent an important component of the diet of Little Egrets but, as aquatic species only, are a very minor component of the diet of Grey Heron.