Tree Species Preferences of Foraging Songbirds During Spring Migration in Floodplain Forests of the Upper Mississippi River: Bird Data

We evaluated bird foraging preferences for tree species during spring migration 2010-2013. We used the point center-quarter method to assess relative availability (tree importance values, IV) of tree species and tallied bird foraging observations on tree species as well as recording the phenophase of used trees on five 40 ha plots of contiguous floodplain forest between La Crosse, Wisconsin, and New Albin, Iowa, from 15 April through 1 June 2010-2013. We quantified bird preferences by comparing proportional use of tree species by each bird species to estimates of tree species availability (IV) for all four years and for each year separately. Bird data records contain the plot identity, date, time of the observation, species of bird, sex if distinguishable, tree species in which it was foraging, location the bird was in the tree, dbh of the tree, phonological phase of the tree and any comments about the observation (foraging in flowers, if tree was in flower, etc.)

本研究于2010—2013年鸟类春季迁徙期，评估了鸟类对林木树种的取食偏好。研究采用中心点四分法（point center-quarter method），评估林木树种的相对可利用性（即林木重要值，IV）；并在威斯康星州拉克罗斯与艾奥瓦州新奥尔宾之间的5块连片泛滥平原林样地（单块面积40公顷）内，统计鸟类取食不同树种的观测记录，同时记录被鸟类取食林木的物候期。观测时段为2010—2013年每年的4月15日至6月1日。本研究通过对比各鸟类物种对林木树种的取食占比，与四年整体及各单年度的林木树种可利用性（IV）估算值，量化鸟类的取食偏好。鸟类观测数据记录包含以下信息：样地编号、观测日期、观测时间、鸟类物种、若可辨识则记录的性别、鸟类取食的林木树种、鸟类在林木上的取食位置、林木胸径（dbh）、林木物候期，以及观测相关备注（如在花部取食、林木是否处于花期等）。