Western Cattle-Egret

Drifting through the hot, salty air, a group of Western Cattle-Egrets follows a herd of Chincoteague ponies, snatching up insects stirred by their hooves. A wading bird of fields rather than water bodies, this species can be found foraging in lawns, meadows, and wet ditches in agricultural habitats. On the Virginia coast, it nests colonially, forming a small part of mixed-species rookeries.

Originally from Africa, Cattle-Egrets arrived in South America in the 1880s, seemingly without human assistance, and quickly spread to North America (Telfair 2024). The species reached Virginia in 1953, when it was first seen on Assateague Island (Valentine 1958). In 2024, taxonomic revisions split the species into Eastern and Western Cattle-Egrets, with the African population and all North and South American birds classified as Western Cattle-Egrets (Chesser et al. 2024).

Breeding Distribution

The Western Cattle-Egret was well-covered during the Second Atlas by the 2018 Virginia Colonial Waterbird Survey, a coastal census conducted by the Center for Conservation Biology in collaboration with the Virginia Department of Wildlife Resources and The Nature Conservancy. The survey identifies nesting locations of this and other species that breed in colonies. Because the Western Cattle-Egret only breeds within the survey area, there was no need to model its distribution. For information on where the species occurs in Virginia’s Coastal Plain, please see the Breeding Evidence section.

Breeding Evidence

The Western Cattle-Egret nests exclusively within the survey area covered by the Virginia Colonial Waterbird Survey in 2018, and this survey documented the locations of breeding colonies of this species. Therefore, the species is unlikely to have nested in blocks without confirmed breeding evidence. Additional breeding confirmations were reported by Atlas volunteers in other years of the Second Atlas period.

Western Cattle-Egret breeding is restricted to a few sites on the Eastern Shore. Breeding was confirmed in only two blocks, both in Accomack County (Figure 1). One colony is on Tangier Island, and two nearby sites are along the Chincoteague Island causeway. The species was sighted during the breeding season in other locations, but none of these sites was found to host breeders.

During the First Atlas, breeding was confirmed in 10 blocks, all on the Eastern Shore except for one in Hopewell along the James River (Figure 2). Most of these breeding sites have now been abandoned by Western Cattle-Egrets as their population has crashed (see Population Status section). For example, Cattle-Egrets disappeared from the colony in Hopewell in the mid-1990s and have never returned (Watts et al. 2024).

Only three individual observations of breeding Western Cattle-Egrets were recorded, limiting the picture of their breeding phenology (Figure 3). On June 9, 2018, there were young in nests on Tangier Island, and later, on June 27, 2018, nests on Chincoteague had eggs. One recent fledgling was reported on July 10, 2020, also at Chincoteague. For more general information on the breeding habits of the Western Cattle-Egret, please refer to All About Birds).

Figure 1: Western Cattle-Egret breeding observations from the Second Atlas (2016–2020). The colored boxes illustrate Atlas blocks (approximately 10 mi² [26 km²] survey units) where the species was detected. The colors show the highest breeding category recorded in a block. The numbers within the colors in the legend correspond to the number of blocks with that breeding evidence category. Nesting is unlikely outside of confirmed blocks.

Figure 2: Western Cattle-Egret breeding observations from the First Atlas (1985–1989). The colored boxes illustrate Atlas blocks (approximately 10 mi² [26 km²] survey units) where the species was detected. The colors show the highest breeding category recorded in a block. The numbers within the colors in the legend correspond to the number of blocks with that breeding evidence category.

Figure 3: Western Cattle-Egret phenology: confirmed breeding codes. This graph shows a timeline of confirmed breeding behaviors. Tick marks represent individual observations of the behavior.

Population Status

The Western Cattle-Egret had too few detections during the Atlas point count surveys to develop an abundance model. However, the distribution and size of Western Cattle-Egret colonies derived from the 2018 Virginia Colonial Waterbird Survey are displayed on the CCB Mapping Portal.

The Virginia Western Cattle-Egret population increased rapidly during the 1960s. By 1962, they had crossed the Blue Ridge Mountains into the Mountains and Valleys region, though not breeding there (Murray 1963). This period did not last. Declines began in the mid-1970s and intensified in the mid-1990s (Watts et al. 2024). Based on the Virginia Colonial Waterbird Surveys, the Western Cattle-Egrets experienced the steepest decline of any monitored species (98%), declining from an estimated 1,459 to only 25 pairs from 1993 to 2023 (Watts et al. 2019, 2024; Figure 4).

Figure 4: Western Cattle-Egret population trend for Virginia’s Coastal Plain. This chart illustrates the number of breeding pairs as estimated by the Virginia Colonial Waterbird Survey (Watts et al. 2024). A data point is not included for 1998, as the Survey covered a smaller geographic area in that year. The vertical light blue bars represent the periods corresponding to the First Atlas (1985–1989) and Second Atlas (2016–2020).

Conservation

Despite past population booms, Western Cattle-Egrets have shown marked declines in the past three decades. This decline has been attributed to ongoing degradation of mixed heronries, in which many colonial-breeding birds are experiencing population declines (Watts et al. 2024). The loss and degradation of breeding sites are driven by not only coastal development but also erosion of islands due to sea-level rise (Watts et al. 2019).

Nonetheless, they are a widely distributed species that has shown the ability to disperse across the globe. Western Cattle-Egret is not currently considered a species of concern in Virginia.

Interactive Map

The interactive map contains up to six Atlas layers (probability of occurrence for the First and Second Atlases, change in probability of occurrence between Atlases, breeding evidence for the First and Second Atlases, and abundance for the Second Atlas) that can be viewed one at a time. To view an Atlas map layer, mouse over the layer box in the upper left. County lines and physiographic regional boundaries (Mountains and Valleys, Piedmont, and Coastal Plain) can be turned on and off by checking or unchecking the box below the layer box. Within the map window, users can hover on a block to see its value for each layer and pan and zoom to see roads, towns, and other features of interest that are visible beneath a selected layer.

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References