Erica H. Dunn

TEMPORAL AND SPATIAL PATTERNS IN DAILY MASS GAIN OF MAGNOLIA WARBLERS DURING MIGRATORY STOPOVER

Abstract Whether or not migrants gain mass at a stopover site is an index of site quality. Previous studies have examined mass gain of recaptured birds, and of short-term stopovers by regressing mass at first capture on hour of day. I developed an extension of the latter method using multiple regression to examine the effects on mass gain of hour of day, date, and year. I then used the method to compare the quality of three stopover sites at Long Point, Ontario, for Magnolia Warblers (Dendroica magnolia). At the peak of fall migration, warblers at all three sites gained sufficient mass for a net gain over 24 h, but they gained mass at only two of three sites during spring. Mass gain varied significantly over the course of the day, by date in the season, and among years. The earliest spring migrants lost mass at all sites, but rate of mass gain increased as the season progressed. Similar information for many more species and stopover sites might aid in habitat conservation for migrants.

Using Migration Counts to Monitor Landbird Populations: Review and Evaluation of Current Status

Increased knowledge of North American landbird populations and concern for their status (e.g., Robbins et al., 1989; Askins et al., 1990; Askins, 1993) has led to greater interest in methods of monitoring population change in nongame birds. Without monitoring we are unable to document long-term change, to determine whether short-term fluctuation is within a normal range, or to evaluate the effectiveness of management.

Monitoring songbird population change with autumn mist netting

Counts of migrating birds potentially could be used to detect population change. This technique would be especially valuable for tracking species poorly monitored by breeding and wintering season counts, such as boreal-nesting songbirds that winter in the tropics. Numbers of migrants counted vary with weather and other factors, however, and we need to demonstrate that migration counts give accurate results. Population trends for 1979-91 were calculated for 13 songbird species captured during autumn mist netting at 2 sites in southern Michigan. All species were northern-nesters occurring at the study sites only as transients. Annual indices of abundance were derived from a multiple regression of daily number of newly-captured birds on independent variables for date, weather, moon phase and year. Trends in the annual capture indices were significantly and positively correlated with trends in breeding bird survey (BBS) data from presumed breeding grounds in Michigan and Ontario, and were of similar magnitude. The results suggest that intensive, standardized netting can be a useful population monitoring tool.

Effects of summer feeding area on gosling growth in Snow Geese

Relative growth of body parts (wing, culmen, tarsus) in young Snow Geese differed among years and among summer feeding areas only a few kilometers apart in the vicinity of the McConnell River, Northwest Territories, Canada. Gosling age was unknown at time of capture, so we expressed all differences in measured characteristics as a function of culmen length. This procedure may underestimate the magnitude of differences in growth with respect to age. Year and summer feeding area had large, independent effects on relative growth. Growth of primary feathers showed the greatest variation of measurable variables among feeding areas. We argue that the cause of most differences in relative growth was nutritional variation of vegetation. If goslings with retarded growth do not entirely catch up on fall staging areas, there may be lasting demographic effects.

Enhancing the value of the breeding bird survey : Reply to sauer et al. (2005)

Abstract Bart et al (2004a) proposed several approaches for enhancing the considerable value of the Breeding Bird Survey (BBS). Sauer et al. (2005) critiqued some of these approaches, and emphasized alternative goals for the survey. We agree with many of the suggestions of Sauer et al. (2005); notably that multispecies, large-scale surveys such as the BBS are most valuable for bird conservation if they achieve multiple objectives. Nevertheless, we strongly assert that estimation of long-term trends is of fundamental importance for identifying important conservation issues and determining which species represent priorities for conservation efforts, as has been repeatedly demonstrated in the past. We are confident that our recommendations for enhancing the ability of the BBS to detect trends—reducing bias, explicitly recognizing that all bias cannot be eliminated, and increasing sample size in poorly covered areas—can only enhance, and not detract from, the value of the BBS for other purposes.

Estimating Proportion of an Age Class Nesting in Canada Geese

We estimated proportions of each age class nesting in a population of small Canada geese (hutchinsii-parvipes complex of Branta canadensis), Northwest Territories, Canada. Because some nonnesters left the breeding grounds before incubation, the time period used for calculating the proportion nesting affected the estimates. Estimates based on observations confined to the laying and incubation periods have probably overestimated proportions nesting, particularly for 2and 3-year-old geese. J. WILDL. MANAGE. 52(3):421-423 The age individuals start nesting and the proportion of birds that nest each year influence productivity of avian populations (Kadlec and Drury 1968, Gaston and Nettleship 1981). The proportion of a population nesting can vary among years (MacInnes et al. 1974, Finney and Cooke 1978) and is a useful indicator of environmental conditions and population status (Kadlec and Drury 1968, Ainley and LeResche 1973, Afton 1984, Aebischer 1986). Despite the potential usefulness of such data, there are few studies of free-flying Canada geese that show the proportions of each age class nesting (Sherwood 1967, Cooper 1978:53-55). Captive geese frequently begin nesting at a later age than wild geese (Cooper 1978) and data from captive geese may not be comparable with data from wild

The American Ornithologists' Union: The First Century, 1883–1983

The American Ornithologists’ Union: The First Century, 1883–1983 by Keir B. Sterling and Marianne G. Ainley; edited by William E. Davis, Jr., and Byron K. Butler. 2016. viiiþ405 pp., 6 appendices, 6 tables, 49 black-and-white photographs.

David John Trevis Hussell, 1934–2015

35 (hardcover). ISBN 978-1-877973-50-5. This volume was commissioned by the AOU to mark its centennial year of 1983. After a manuscript was produced, it languished for 30 years, for reasons detailed in the preface to the book (a story in itself ). I played a role in its revival—full disclosure—and the reasons I was eager to do so form the basis of this review. Written by two historians, the book brings together material from correspondence, interviews, and extensive archival records. It makes for unexpectedly interesting and even lively reading, despite chapter headings such as ‘‘By-Laws’’ and ‘‘Classification and Checklists.’’ The history of the AOU is displayed with all its ups, downs, and inevitable controversies, enlivened with quotations that reveal (and sometimes revile) the personalities that so often prove crucial in shaping real-life events. Background on parallel developments in North American science and society place the AOU’s evolution in a broader context. Each chapter is focused on an area of particular importance to governance or activities of the AOU, such as publication, annual meetings, and bird protection. This approach highlights key developments in each area that would have been obscured in a strict chronology, yet allows overarching themes to emerge. The AOU’s first 100 years divide roughly into three broad eras: a founding era (1883 to mid-1930s), a period of transition to a modern era (1930s to 1960s), and a final 15–20 years of rapid modernization. The particulars for the AOU are doubtless unique, but the overall picture of change within the AOU must surely be similar to the challenges every scientific society has faced in changing times: What is the main purpose of a scientific organization and how are its goals best accomplished? What should the scope and standards be for the journal? Who should control society governance? In its early years, the AOU was literally an old-boys network, as was the norm of the age. Because the original focus was classification and nomenclature, the governance structure restricted decision making to a small group of recognized experts. Among its earliest activities, the AOU set rules for itself on taxonomic decision making and nomenclature that influenced rules adopted later by ichthyologists and mammalogists in North America, as well as international rules developed in Europe. Over the years, AOU Checklist iterations shifted in emphasis on splitting vs. lumping as the causes of variation in form became better understood. (Americans in the early days of the AOU were more Lamarckian than Darwinian.) In addition to this core activity, enthusiastic and active committees worked on the study of distribution, migration, and protection of birds. Criteria were soon broadened to expand (nonvoting) membership, which grew quite rapidly, though it took decades of incremental change to democratize the Union’s governance. The transition period of AOU history is captured in quotations concerning remarks made by President Herbert Friedmann in 1938 that summarized past accomplishments and looked to the future (pp. 43–44). He noted that

Caloric Intake of Nestling Double-Crested Cormorants

David Hussell, whose ornithological contributions included important studies on the reproductive strategies of Arctic birds and the Tree Swallow, and who is known to many in Canada as the ‘father of migration monitoring’ for his leading roles in the development of the Long Point Bird Observatory and the Canadian Migration Monitoring Network, died suddenly of a brain hemorrhage on April 10, 2015. Aged 80, he was still active in field work and preparing manuscripts. David is survived by his wife, sons Jeremy and Peter, and two grandsons. David was born in Winchester, England, in 1934, and later moved with his three siblings toWelwyn Garden City, just north of London. Other than David, his family was not much interested in birds, but he was given a copy of James Fisher’s 1941 book,Watching Birds, which contained a list of natural history organizations. Through some of those contacts, David met a few local children with similar interests. Within several years they were riding bicycles from London to the coast to visit bird observatories. David soon earned his ringing permit, and his siblings remember him trapping birds in the backyard with a drop-box triggered by pulling a string inside the house, where David was ostensibly doing homework. Despite this interest, David didn’t realize ornithology could be a career, and he went to the University of London to follow his father into civil engineering. He nonetheless kept in touch with friends who were biology students at Oxford and joined them on several camping trips to study birds, including one to northernmost Norway to document behavior of Redwings in continuous daylight. This trip was notable in spurring David’s lifelong interest in Arctic birds, and introducing him to scientific study. (Also during this trip, the party stepped through a reindeer fence to set foot briefly in Russia—doubtless not advisable today.) After earning a postgraduate diploma in concrete technology, David immigrated to Canada, in part to avoid mandatory military service in England. He arrived in Toronto in 1957 without any job prospects, but times were different then, and within weeks he was hired by the rapidly expanding Ontario Department of Highways. Almost as quickly, he joined the recently formed Ontario Bird Banding Association. They had ambitions of starting a chain of British-style bird observatories along the shores of the Great Lakes, and in 1959 David was part of a small group exploring possibilities for a station at Long Point, on Lake Erie’s northern shore. He played a lead role in founding the Long Point Bird Observatory (LPBO) in 1960. That same year David took a leave of absence from the Department of Highways to study breeding behavior of