Common Egret And Great Blue Heron Nest Study

Author : Margaret Maginley Meserve
Publisher :
ISBN 13 :
Total Pages : 68 pages
Book Rating : 4.:/5 (945 download)

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Download or read book Brood Provisioning and Nest Survival in the Great Blue Heron (Ardea Herodias) written by Margaret Maginley Meserve and published by . This book was released on 2013 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Altricial birds are dependent on their parents for thermoregulation, nutrition, and protection from predators. They experience rapid growth during the post-hatching period and grow to nearly adult size by the time they fledge. Wading birds such as herons, egrets, and ibis provide parental care for longer periods than most other species with altricial young. Adult Great blue herons (Ardea herodias) (GBHE), the largest wading bird in North America, provide parental care for approximately four months. This species forages in a wide variety of wetland and early successional habitats, is generally piscivorous, abundant in most coastal areas, and long-lived. From 1983-2009 the number of coastal breeding pairs of Great blue heron (GBHEs) in Maine declined by 64% and the number of occupied islands on which these birds breed declined by 40%. In 2007 the Maine Department of Inland Fisheries and Wildlife listed the GBHE as a Species of Special Concern, and in 2009 expanded its annual monitoring to include inland colonies. However, it is unknown if the associated pressures on populations nesting in inland colonies are the same as the coastal colonies. This study compared the relationship between parental care and nest survival of GBHEs in one coastal and one inland colony. With a total of 411 hours of colony monitoring and 123 observed brood provisioning events; this study is the most thorough examination of parental care and nestling behavior of GBHEs in the northeastern portion of their range. Brood provisioning rates in the first two weeks post-hatch were significantly greater in the inland site (n=11; nests) however this difference did not affect nest fate (>̲ 1 chick fledged). Brood provisioning rates in 2-4 week old chicks differed between sites with greater rates of provisioning in the coastal site. In both sites the number of nestlings within a nest was positively correlated with the number that subsequently fledged per nest (inland: n=41; coastal: n=35). Daily nest survival was positively associated with an increasing number of nestlings, earlier hatch dates, and increased brood provisioning rates for 1-2 week old chicks. These results suggest that the number of nestlings per nest can be used as a proxy for nest success in GBHE colonies in the northeastern part of their range.