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Dispersal and habitat use by post-fledging juvenile snowy egrets and black-crowned night-herons

June 16, 2010

We studied the postfledging dispersal movements and habitat use of juvenile Snowy Egrets (Egretta thula) (SNEG) and Black-crowned Night-Herons (Nycticorax nycticorax) (BCNH) in coastal Virginia using a dye (picric acid) and radiotelemetry. Results from monitoring radiomarked birds revealed significant differences both years between species, with SNEGs dispersing more widely than BCNHs. BCNH juveniles usually remained south of Delaware, but SNEGs often moved into Delaware and southern New Jersey. The maximum dispersal distance found for a SNEG was ca 340 km north of the natal colony. Temporal patterns of movement followed logistic relationships, with rapid initial movements, but relatively few movements after about 23 weeks for most birds. Cumulative distances moved by juvenile SNEGs during AugustSeptember differed from 1992 to 1993. No such year difference was found for BCNHs. Compared to SNEGs, BCNHs used man-made impoundments relatively more often than natural wetlands; however no quantitative assessment of habitat preferences could be made.

Citation Information

Publication Year 1996
Title Dispersal and habitat use by post-fledging juvenile snowy egrets and black-crowned night-herons
Authors R.M. Erwin, J.G. Haig, D.B. Stotts, J. S. Hatfield
Publication Type Article
Publication Subtype Journal Article
Series Title The Wilson Bulletin
Index ID 5223097
Record Source USGS Publications Warehouse
USGS Organization Patuxent Wildlife Research Center