Forest Birds of the Last Green Valley
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Forest Birds of the Last Green Valley: The Density Distribution, Habitat Ecology, and Conservation of the Forest Birds of Eastern Connecticut Robert J. Craig Bird Conservation Research, Inc. 90 Liberty Highway Putnam, CT 06260 Michael Altshul Green Valley Institute College of Agriculture and Natural Resources University of Connecticut 139 Wolf Den Rd. Brooklyn, CT 06234 Kathleen G. Beal Department of Biology 300 College Park University of Dayton Dayton, OH 45469-2320 Sponsored by Quinebaug-Shetucket Heritage Corridor, Inc. Perry Heights Press Bird Conservation Research, Inc. Contribution No. 11 Bird Conservation Research, Inc. Contribution Series Edited by Robert J. Craig Board of Trustees Mary Eliza Kimball, President June A. Schoppe J. Kemler Appell David B. Schroeder Gregory M. Castanza Katherine Sheldon Gertrude Lamb Ronald. J. Tillen Judith Radasch Donald E. Williams The Contributions Series is published at irregular intervals by Bird Conservation Research, Inc., 90 Liberty Highway, Putnam, CT 06260, USA. The series focuses on basic and applied studies of bird conservation. Shorter publications and newsletters are available online at www.birdconservationresearch.org. Cover illustration: Forest, by Barbara A. Lussier © Bird Conservation Research, Inc. 2003 All rights reserved. This work may not be reproduced in any form without the written permission of the publisher (Bird Conservation Research, Inc., 90 Liberty Highway, Putnam, CT 06260, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. First published 2003 ISBN 978 0-9747973-0-4 i Craig, Altshul and Beal FOREST BIRD COMMUNITIES Contents Introduction ............................................................................................................................. 1 Methods ................................................................................................................................... 2 The environment ............................................................................................................ 3 Study areas ..................................................................................................................... 8 Bird surveys ................................................................................................................... 13 Analysis ......................................................................................................................... 13 Data strengths and limitations ....................................................................................... 19 Results and discussion ......................................................................................................... 19 Habitat ............................................................................................................................ 19 Bird surveys ................................................................................................................... 20 Species accounts ............................................................................................................ 26 Species detected incidentally to surveys ....................................................................... 187 Literature cited ...................................................................................................................... 188 Index ........................................................................................................................................ 195 ii Craig, Altshul and Beal FOREST BIRD COMMUNITIES Foreword One might say that the forest flew north on the wings of birds. Our present forests, dominated as they are by oaks, began their tenure on the Connecticut landscape about 6,000 years ago. From their scattered refugia in the Southeast, oaks colonized the emerging post- glacial landscape as acorns were dispersed by species like the lowly Blue Jay. Although it would be simplistic to assert that these forests were established solely by the actions of birds, certainly birds were one of the key agents of dispersal for the large-seeded oaks. We may, therefore, think of two communities, one of trees and one of birds, as being intimately connected since their origins. In this volume, the legacy of this long relationship is documented. This work records for the first time patterns of bird species diversity and community population density for eastern Connecticut. Moreover, it details the distribution and density of individual bird species in this region. The densities of populations studied show numerous associations with habitat, and density patterns show as well a relationship with broad geographic patterns in habitat distribution. The elucidation of these patterns, both for community parameters and for individual species, provides tools for understanding the ecological processes that drive distributions. In addition to providing insights into large-scale ecological phenomena, this volume is intended to be a database for the resource management community. Lessons to be gleaned from the data provided include (1) even common forest birds are not distributed uniformly across the landscape, (2) forest bird species exhibit highly heterogeneous habitat needs and (3) there is a profound summer-winter shift in the distributions of even “permanent resident” species. As a consequence, (4) no one forest tract, even a large one, supports the entire compliment of forest bird species. Each tract is demonstrated to have its own characteristics, which favors certain species and discourages others. Hence, only protection of a series of such tracts appears likely to ensure the long-term persistence of the regional forest bird community. Despite the enormous volumes of data gathered and synthesized to produce this work, the research presented is of a snapshot in time. It may be thought of as a starting point, and not yet a complete statement, for understanding the processes driving large-scale patterns in our regional forest bird community. Robert J. Craig Putnam, Connecticut 2003 iii Craig, Altshul and Beal FOREST BIRD COMMUNITIES Acknowledgments This study was made possible by grants from the Quinebaug-Shetucket Heritage Corridor, Inc., the Pfizer Foundation and contributions from the membership of Bird Conservation Research, Inc. Printing was made possible through a gift provided by Perry Heights Press LLC and contributions of species sponsors. The Connecticut Cooperative Extension System, Green Valley Institute and University of Dayton donated staff time to the study and provided access to Geographic Information Systems software. Individuals who actively promoted the successful completion of the study include Alfred Boote, Stephen Broderick, Edward Clement, Charlene Cutler, Eliza Kimball, Barbara Lussier, Alexander Rotival, Eric Thomas, Ronald Tillen and Donald Williams. The enormous data sets generated during investigations were computerized by Holly Bik, Steven Gilbert and Daniel Kita. iv Craig, Altshul and Beal FOREST BIRD COMMUNITIES INTRODUCTION Historical background.- The avifauna of Connecticut has been the subject of major Although not precisely a valley, the historical surveys, including those of Linsley drainages of the Quinebaug, Shetucket, and (1843), Merriam (1877), Sage et al. (1913), Thames Rivers of eastern Connecticut do Mackenzie (1961), Manter (1975), Zeranski indeed encompass an area that is still green. and Baptist (1990), and Clark (1999). Some of the greatest remaining expanses of Furthermore, Dowhan and Craig (1976) and natural landscapes from Washington to Craig (1979) reported the historic distribution Boston characterize the region (Rosenberg et and conservation status of rare Connecticut al. 1999). However, eastern Connecticut is birds. Principal large scale, quantitative rapidly growing (Connecticut Office of Policy surveys of Connecticut birdlife include works and Management 2002), and within one more by Askins et al. (1987), Craig (1987, 1990), generation this landscape is likely to undergo and Bevier (1994). Moreover, Breeding Bird a revolution in appearance. Throughout the Surveys (U.S. Fish and Wildlife Service), East Coast, similar revolutions are underway, Christmas Counts (National Audubon and it appears left to the present generation to Society), and Summer Bird Counts make critical decisions about the future (Connecticut Ornithological Association) (e.g. persistence of the region’s natural features Zeranski and Purnell 2001) are run annually. (Craig 2002). However, making sound These three efforts yield information on conservation decisions requires an extensive relative abundance. Furthermore, aerial mid- resource database. Hence, a key goal of this winter counts of coastal waterfowl numbers investigation is to provide a broad scale are conducted each year by the Connecticut database for the region's forest avifauna. Department of Environmental Protection In addition to their value in documenting (Merola 1991). resource distribution, broad scale studies At present, the most complete source for permit investigation of ecological processes summer distributions of Connecticut birds is that operate at the landscape level. Scale is a The Atlas of Breeding Birds of Connecticut critical issue in interpreting ecological (Bevier 1994). Breeding bird atlases of this phenomena, in that differing community type have