Date of Award:

5-1947

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Department name when degree awarded

Zoology

Committee Chair(s)

J. S. Stanford

Committee

J. S. Stanford

Abstract

Herons are well known because of their gregarious nesting habits. Like many others of the lower orders of birds they nest together in pure or mixed colonies of many different combinations and under diverse living conditions. The population of different colonies may vary from a few pairs to many thousands of pairs depending upon the nature and extent of the breeding area, the food supply available and the protection afforded either by natural or artificial means.

In Utah and adjacent areas of bordering states, many types of heron associations have been studied and reported by ornithological workers. Breeding colonies of Treganza Herons, Black Crowned Night Herons and Snowy Herons in pure species associations and mixed communities have been recorded. The tendency of herons to associate with other unrelated orders of birds in nesting situations has also been noted. Such colonies as the Gull-Pelican-Heron associations of the Great Salt Lake Islands and the Heron-Cormorant communities of Cache Valley and Bass Pond Reservoir support this observation. At least eight different communal associations involving herons in the nesting season are known in Utah. These are listed as follows:

(1) Treganza Heron (pure species association) colonies are found near Bear Lake in Southern Idaho20 and in the Bear River Marshes near Corinne, Utah.

(2) Pure species colonies of the Black Crowned Night Heron are known in various marshes of the State.

(3) Pure species colonies of Brewster's Egret (Snowy Heron) occur in the tules of the Bear River Marshes near Corinne, Utah.29

(4) Black Crowned Night Heron and Brewster's Egret colonies have been observed in southern central and northern Cache Valley33, Bear Lake region in southeastern Idaho20 and in the Bear River Marshes.29

(5) The Treganza Heron, Black Crowned Night Heron and Brewster's Egret nest together in Cache Valley, Utah, in two different colonies.33

(6) Colonies of the Treganza Heron and Double Crested Cormorant are known from Cache Valley33, Great Salt Lake Islands36 and Bass Pond Reservoir.29

(7) Brewster's Egret and the White Faced Glossy Ibis have been seen nesting together in the tules of the Bear River Marshes.29

(8) The California Gull, White Pelican and Treganza Heron nest together in colonies on the islands of the Great Salt Lake.24, 36

Published accounts of heron colonies and associations involving nesting herons in Utah have dealt largely with the location and history of the colonies, the numbers of individuals present, nests and general food habits. Other species of animals have been noted about the nesting area in only a few instances, and the relationships of these animals to the nesting birds have not been worked out. There is a lack of knowledge concerning the part played by mammals, reptiles, insects and other types of animal life in the welfare of the bird communities.

The question of the economic status of herons has long been debated among ornithologists and those engaged in the propagation of wild life, especially fish culture. The fish eating propensities of herons are known all over the world. In some regions the birds are condemned as a menace by the sportsman and in other areas they are considered to be his benefactors. Adequate studies have not been published to definitely establish the economic status of this group of birds.

It is the purpose of this thesis to contribute to the knowledge of Ornithology by a presentation of the writer's observations and findings on a colony of nesting herons, noting, especially, certain factors influencing the behavior of the birds, their relationships to other animals of the community, economic importance and development of the colony.

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This work made publicly available electronically on April 24, 2012.

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