Cattle Egret

Male Cattle Egret in breeding plumage

The Cattle Egret, a stocky heron that usually isn't seen these days in the Lehigh Valley, was spotted twice in Northampton County last week. 

One sighting was reported at the Silver Creek retention pond in Bath on May 29. A second was reported at Seiple's Pond in nearby East Allen Township, also on May 29. Dave DeReamus, of the Eastern PA Birdline, said it's likely that the two sightings were of the same bird.

Native to Africa, the Cattle Egret has undergone one of the fastest and wide-ranging expansion of any bird species. For untold centuries they have been hopping behind the feet of elephants, zebra, rhinos and gazelle, foraging for insects that are stirred up in the grass. They also ride the backs of large grazing mammals, picking and consuming ticks and flies.

Somehow a few birds crossed the Southern Atlantic Ocean to the Guianas (the present-day countries of Guyana and Suriname) in the late 19th century. By the 1930s they had established colonies there. The first sightings in the United States occurred in 1941. By the 1960s the species was flourishing in croplands and pastures. Within a decade colonies reached Canada.

Cattle Egrets follow herds of North American cattle, much as the large land grazers of Africa do. Grasshoppers, crickets and flies form a major part of the Cattle Egret's diet. The birds also take advantage of farm machinery as it churns up ground that harbors insects, larvae, maggots, earthworms and snakes. When smoke is seen coming from a field, Cattle Egrets fly toward the fire, consuming insects as they flee. The birds supplement their diet with moths, frogs, fish and sometimes the eggs of other birds. 

Spread of Cattle Egrets in 20th Century

"Their rapid spread stems from versatile feeding and breeding abilities, an aptitude for dispersing to new areas, and a changing landscape: they gained foraging habitat as people converted land for livestock production and crops," the Cornell Lab of Ornithology observes.

Cattle Egrets are smaller and more compact than other heron species. Their legs are shorter, their necks shorter and thicker, and their bill daggerlike but short. 

Their habitat differs as well. They are less likely to be seen in water than other herons. Instead they are apt to be seen on farms, in pastures and plowed fields, near marshes and wetlands, and even along roadsides.

Cattle Egrets form colonies for breeding, often intermingling with other herons. The male establishes the nesting site but the female usually does the building. The nests, located in marshland or in trees beneath streams, are shallow bowls of sticks, twigs and vines lined with soft plants. The female lays three to four eggs (but occasionally as many as nine). The young begin to fly in 25 to 30 days and are fully independent 45 days after birth.

In the northern United States, Cattle Egrets migrate during the autumn and spend their winters in the Deep South where temperatures rarely fall below 40 degrees and food remains abundant. However a few birds have wintered along coastal waters as far north at Rhode Island.

Cattle Egrets do not have many predators, except for mammals and birds who raid their nests for eggs. Animals that have been known to prey on adult Cattle Egrets are Red-tailed Hawks, red foxes and bobcats.

The National Audubon Society ranks the Cattle Heron, a newcomer to North America, as a species of "least concern" for population decline.

That is not so in the Lehigh Valley, however. The first documented sighting of a Cattle Heron occurred in May 1960 at Spring Creek. Ironically, although the birds continued to spread across the United States, reported sightings in the Lehigh Valley have become rare, according to Birds of the Lehigh Valley and Vicinity, the authoritative guidebook of the Lehigh Valley Audubon Society.

Could it be that Cattle Herons are uncommon here because so many farms have been converted into office and industrial parks, suburban housing and shopping malls?