Determinants of great blue heron colony distribution in coastal Maine
Determinants of great blue heron colony distribution in coastal Maine
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缅因州沿海大蓝鹭群体分布的决定因素
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发表时间：
1987
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通讯作者：
Alan E. Hutchinson
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作者：
J. Gibbs;Susan L. Woodward;M. Hunter;Alan E. Hutchinson
通过考察大蓝鹭（Ardea herodias）在缅因州沿海筑巢时群体大小与附近食物供应、筑巢生境选择和群体间距之间的关系，研究了大蓝鹭在缅因州沿海筑巢时的分布。19个殖民地（大小范围4-252巢），位于海洋岛屿。在一个殖民地的巢数呈正相关（r = 0.82）与面积的潮汐和内陆湿地在20公里半径的殖民地。巢和殖民地的特点是高度可变的，合适的筑巢栖息地似乎并没有限制殖民地的大小或分布。造林的程度，硬木的存在，和距离城镇和其他岛屿殖民地的岛屿显然是重要的因素在选择筑巢岛屿。殖民地均匀分布在沿着，间隔约16公里。我们提出了一个模型的基础上观察到的扩散苍鹭巢的结论，即同一殖民地的成员之间的食物竞争可能限制了殖民地的大小，而相邻殖民地的成员之间的食物竞争可能会决定殖民地的分布。1986年2月7日收文，1986年6月16日接受。许多研究人员已经研究了在群体中筑巢的价值（Lack 1968，Ward和Zahavi 1973，Hoogland和谢尔曼1976，Krebs 1978，Burger 1981，Gotmark和Andersson 1984），但是对于是什么决定了一群鸟在哪里形成一个群体或者这个群体有多大，人们了解得很少。殖民地位置的决定因素往往补充因素，有助于殖民筑巢行为。两个例子是通过选择难以接近的筑巢地来增加对捕食者的保护（例如Cullen 1957，Burger和Lesser 1978，纳尔逊1978），以及通过在食物资源附近筑巢来提高资源利用率（Ward和Zahavi 1973; Kushlan 1976 a，1978）。一个群体中个体数量的决定因素还不太清楚。在其他因素中，对位置的竞争可能会限制群体的大小，即在群体中繁殖的个体数量，在某些群体中，例如某些苏鱼（纳尔逊1966年），而食物的可用性可能会限制集群大小在鹭科（Werschkul等，1977年，McClammon 1978年，Beaver等，1980年）、phalacrocoracids、alcids、sulids和larids（Fur 3目前地址：美国密苏里州密苏里州，哥伦比亚，密苏里-哥伦比亚大学，塔克大厅105号，生物科学系，邮编：65211。ness和Birkhead 1984）。测量食物供应和群体大小之间的关系是困难的，因为群体鸟类使用的食物资源通常是零散和临时的，并且分布在群体周围的广阔区域。我们的目的是研究可能的决定因素的分布筑巢大蓝鹭（Ardea herodias）在沿海地区的缅因州。筑巢的大蓝鹭是大而显眼，因此殖民地的位置和大小可以很容易地确定在一个大的区域。大蓝鹭也主要在当地相对永久的湿地栖息地觅食。群体大小与食物资源可用性指数（即湿地可用性）之间的关系很容易确定。我们描述了该地区的大蓝鹭的巢分散的模式。然后，我们研究了在一个殖民地繁殖的苍鹭数量和觅食栖息地的可用性之间的关系;通过比较筑巢区的特征，但未使用的，区域的苍鹭筑巢栖息地的选择;和殖民地的间距。
-The distribution of nesting Great Blue Herons (Ardea herodias) in coastal Maine was studied by examining the relationship between colony size and availability of food supplies near colonies, the selection of nesting habitat, and the spacing of colonies. Nineteen colonies (size range 4-252 nests) were located, all on marine islands. The number of nests in a colony was correlated positively (r = 0.82) with the area of tidal and inland wetlands within a 20-km radius of a colony. Nest and colony characteristics were highly variable, and suitable nesting habitat did not seem to limit colony size or distribution. The degree of forestation, presence of hardwoods, and distance of an island from towns and other islands with colonies were apparently important factors in selection of nesting islands. Colonies were uniformly distributed along the coast at intervals of about 16 km. We present a model for the observed dispersion of heron nests based on the conclusion that food competition between members of the same colony probably limits the size of colonies, whereas food competition between members of adjacent colonies may determine colony distribution. Received 7 February 1986, accepted 16 June 1986. THE value of nesting in colonies has been examined by a number of workers (Lack 1968, Ward and Zahavi 1973, Hoogland and Sherman 1976, Krebs 1978, Burger 1981, Gotmark and Andersson 1984), but less is understood of what determines where a group of birds will form a colony or how large that group will be. Determinants of colony location tend to complement factors that contribute to colonial nesting behavior. Two examples are increased protection from predators through the selection of inaccessible nesting grounds (e.g. Cullen 1957, Burger and Lesser 1978, Nelson 1978) and enhanced utilization of resources by nesting close to food resources (Ward and Zahavi 1973; Kushlan 1976a, 1978). Determinants of the number of individuals in a colony are less well understood. Among other factors, competition for sites may limit colony size, i.e. the number of individuals breeding in a colony, in some groups, e.g. some sulids (Nelson 1966), while food availability may limit colony size in ardeids (Werschkul et al. 1977, McCrimmon 1978, Beaver et al. 1980), phalacrocoracids, alcids, sulids, and larids (Fur3Present address: Division of Biological Sciences, 105 Tucker Hall, University of Missouri-Columbia, Columbia, Missouri 65211 USA. ness and Birkhead 1984). Measuring a relationship between food availability and colony size is difficult because food resources used by colonial birds are typically patchy and temporary and are spread over vast areas around colonies. Our purpose was to examine possible determinants of the distribution of nesting Great Blue Herons (Ardea herodias) in the coastal region of Maine. Nesting Great Blue Herons are large and conspicuous, and thus colony locations and sizes can be readily determined over a large area. Great Blue Herons also feed primarily in local, relatively permanent, wetland habitats. Relationships between colony size and an index of food resource availability, i.e. wetland availability, can be determined easily. We describe the pattern of nest dispersion for Great Blue Herons in the region. We then examine the relationship between the number of herons breeding in a colony and availability of foraging habitat; the selection of nesting habitat by herons by comparing the characteristics of nesting areas with those of similar, but unused, areas; and the spacing of colonies.