Cattle Egret

Bubulcus ibis

These gregarious mid-20th century immigrants to the United States are becoming an increasingly common sight in Missouri, especially during late spring and early fall when they migrate through the state. Adults are distinguished from similar small, white ardeids by their yellow bills and legs and their tendency to forage in association with grazing animals or behind farm machinery. Adult males and females share a high breeding plumage of orange plumes on the crown, back and neck. Nesting colonies can reach densities of several hundred nests per hectare. Telfair (1983) reported a maximum nest density of one nest per 0.77 square meters in Texas.

Code Frequency

Many of the Cattle Egrets seen in Missouri are not associated with nearby breeding colonies but are likely migrating to breeding colonies in the upper Midwest. Because this species also disperses after breeding (Telfair 1994), some seen in summer likely nested elsewhere earlier in the year. Also, Cattle Egrets will travel up to 32 kilometers from breeding colonies to secure food (Bateman 1970). Considering all of the above, the sighting of Cattle Egrets in a block, with no further evidence of breeding, contributed little information about the species' breeding distribution.

Distribution

The Atlas Project did not confirm breeding despite known breeding in the state outside of Atlas Blocks. Only possible breeding codes were recorded for this species. Most were in the Mississippi Lowlands, and likely were associated with known breeding colonies in and near Sikeston in Scott County, near Charleston in Mississippi County and near Caruthersville in Pemiscot County.

Abundance

Within the Charleston colony, the number of breeding Cattle Egrets ranged from 250-1,000 during the Atlas Project while the number ranged from 70-1,200 at the Caruthersville colony. A maximum of about 100 nested at the Sikeston sites.

Phenology

Observations independent of the Atlas Project at the Charleston and Caruthersville colonies revealed Cattle Egrets initiate breeding upon arrival at the colony in late April. Egg laying occurs from early May to early June and most fledging occurs from early June through August. Renesting is apparently commonplace, probably because of disturbance resulting from the density of nests. As a result, some clutches were still being incubated following the fledging of birds from other nests. Cattle Egrets will produce a second brood in the southern United States (Telfair 1994) but it is unclear whether Missouri's late broods were second broods or cases of renesting.

Breeding Evidence

Reported in 320 (26.5%) of 1,207 blocks

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