Clayton M. White

PEREGRINES AND PESTICIDES IN ALASKA

Long esteemed for its functional beauty and prowess as a hunter, the Peregrine Falcon (Falco peregrinus) is the most wide-ranging predatory bird. Breeding populations still occur on every continent and on most of the larger islands of the world. These falcons are noted for their tenacity in holding to traditional nesting sites-usually cliffs-year after year, and their breeding populations have been characterized by a high degree of stability through time, even in the face of extensive human modification and disruption of their environment (Hickey 1942; Ferguson-Lees 1951; Cade 1960; Ratcliffe 1962). In Great Britain, where the species has been most thoroughly studied, until recently the breeding population of some 600 pairs appeared to have changed little since Elizabethan times, when these falcons were much in demand for the

Gene flow and genetic characterization of Northern Goshawks breeding in Utah

Abstract Adult movement and natal dispersal data demonstrate that Northern Goshawks (Accipiter gentilis) are able to travel over long distances, suggesting a large functional population. However, these data are unable to determine whether these movements contribute to gene flow among adjacent breeding areas. We used eight microsatellite DNA loci and mitochondrial DNA control-region sequence data to assess population structure of Northern Goshawks breeding in Utah. Goshawks had moderate levels of genetic variation at microsatellite loci (observed heterozygosity = 50%), similar to levels found in other medium-sized, highly mobile birds. Overall estimates of interpopulation variance in microsatellite alleles (FST = 0.011) and mtDNA haplotypes (ΦST = 0.126) were low and not significantly different from zero. Pairwise population comparisons using microsatellite markers revealed no differentiation among sampled sites, indicating that the functional population extends beyond Utah. However, pairwise population analyses of mtDNA uncovered a single case of differentiation between goshawks inhabiting Ashley National Forest, in northeastern Utah, and Dixie National Forest, in southwestern Utah. Low levels of population structuring observed in mtDNA between the two forests may be due to the smaller effective population size sampled by mtDNA, a cline of haplotypes across the West, or the presence of a contact zone between A. g. atricapillus and goshawks of southern Arizona and the Mexican Plateau. Flujo Genético y Caracterización Genética de Accipiter gentilis Reproduciéndose en Utah Resumen. Datos sobre el movimiento de los adultos de Accipter gentilis y la dispersión natal demuestran que A. gentilis es capaz de viajar largas distancias, lo que sugiere una gran población funcional. Sin embargo, dichos estudios no son capaces de determinar si estos movimientos contribuyen al flujo genético entre las áreas de reproducción. En este estudio se utilizaron ocho loci de microsatélites de ADN y secuencias de la región control del ADN mitocondrial para estimar la estructura poblacional de la unidad reproductiva de A. gentilis en Utah. Este halcón presentó niveles intermedios de variación genética en loci de microsatélites (heterocigosidad observada = 50%), similares a los niveles encontrados en otras aves de tamaño medio con gran dispersión. La estimación total inter-poblacional de la varianza en alelos de microsatélites (FST = 0.011) y haplotipos de ADNmt (ΦST = 0.126) resultaron ser bajas y no significativamente diferentes de cero. Las comparaciones entre pares de poblaciones utilizando marcadores de microsatélites no mostraron diferencias entre los sitios muestreados, indicando que la población funcional se extiende más allá de Utah. Sin embargo, el análisis con ADNmt entre pares de poblaciones mostró en un sólo caso una diferenciación entre la población de A. gentilis que habita en el Bosque Nacional Ashley al noreste de Utah y la población de A. gentilis del Bosque Nacional Dixie, al sureste de Utah. Los niveles bajos de estructura poblacional observados con ADNmt entre los dos bosques pueden deberse a un bajo tamaño poblacional efectivo muestreado con ADNmt, a una disminución de haplotipos hacia el oeste o a la presencia de una zona de contacto entre A. g. atricapillus y Accipiter gentilis del sureste de Arizona y la meseta Mexicana.

The annual lipid cycle and feeding behavior of Alaskan redpolls

SummaryTotal lipids were extracted from 161 redpolls (Acanthis spp.) collected each month of the year from October 1962 to September 1963, in interior Alaska. A lipid index (Weight of ether extract x100/live body weight) was calculated for each sample. Lipids were also extracted from sections of pectoral muscle, livers and hearts representing each month.Body weight and lipid index were significantly positively correlated being highest in January and lowest in September. Total lipid content was significantly inversely correlated with air temperature; the high autumn and spring pre-migratory lipid peaks of migratory species were only weakly expressed in the redpolls. Liver lipid showed a significant annual variation being highest in December and lowest in August, while lipid from heart and pectoral muscle did not vary seasonally.Five birds were held in captivity during spring and summer at a constant temperature of 22°C. Food consumption was 5.1 g/day or 22.4 kcal. The caloric value of the most extensively utilized natural food, birch seed (Betula papyrifera), was determined (5.4–5.5 kcal/g dry wt). When esophageal diverticulae are full (2.0 g wet wt) of birch seeds, the resulting energy yield may sustain an individual for only a fraction of a 24 h winter day in contrast to other arctic herbivores (e.g. ptarmigan, Lagopus sp.) in which a full crop may suffice for the full 24 h period.

Birds of Washington: Status and Distribution edited by Terence R. Wahl, Bill Tweit, and Steven G. Mlodinow

One of the early, classic state bird books, co-authored by William Dawson and J. Hooper Bowles, was The Birds of Washington, published in 1915. Then in 1953 came the important multi-authored Birds of Washington State by 4 authors: Stanley Jewett, Walter Taylor, William Shaw, and John Aldrich. Now the days of detailed and comprehensive state bird books authored by but a few people are a thing of the past. This new book, Birds of Washington: Status and Distribution, has 3 editors who are ornithological and regional experts and contains species accounts and informative essays from nearly 50 contributing authors. It is the definitive book on birds of Washington state. Two major contributions of this new book are the up-to-date distributional maps and a discussion of the change in status and distribution of species over the 50 years since the Jewett et al. book. Not only are 483 bird species covered in the book (many accounts occupying a full page and containing such headings as Subspecies, Habitat, Occurrence, Remarks and Noteworthy Records), but there is a 10page discussion on bird habitats in Washington (in which 30 distinct habitats are listed), a 7-page discussion on avian conservation, and a section on the evolution of field ornithology in Washington. Because the logistics of coordinating so many authors were difficult, this book was more than a decade in the making. The cut-off date for abundance and status change was set at the year 2000; however, records up to at least 2002 are given. A graph showing the known range of dates of occurrence in both the eastern and western portion of the state accompany many species accounts. Over half of the species have shown a change in status over the past 50 years. Examples are (1) the anthropogenic range expansions of the Barred Owl (Strix varia), Anna’s Hummingbird (Calypte anna), European Starling (Sturnus vulgaris), and House Finch (Carpodacus mexicanus) due to favorable habitat modifications and (2) the natural range expansions, perhaps related to climatic changes, of the Black-headed Grosbeak (Pheucticus melanocephalus), Lazuli Bunting (Passerina amoena), and Tricolored Blackbird (Agelaius tricolor). In cases of observed declines in status or distribution, the causes varied, but many were associated with habitat conversion and other human activities rather than natural events. This book is well worth having on your bookshelf, especially if you are interested in birds of the western United States and southwestern Canada. The moderate price, as such books go, makes it an attractive purchase, especially considering that comparable books such as Birds of the Yukon Territory exceed

Breeding population fluctuations in some raptors

120.

Observations on Food, Nesting, and Winter Populations of Large North American Falcons

SummaryWe investigated differences in annual breeding population stability and its relationship to diversity in food habits for several species of raptors. Chi-square tests showed no significant differences between observed and expected (based on logistic growth equation) breeding population sizes for Peregrine Falcons (Falco peregrinus) during recovery from pesticide induced declines in 4 Alaskan populations. This indicates that no major Peregrine Falcon population fluctuations occurred aside from the recovery itself. On the Colville River, Alaska, Rough-legged Hawk (Buteo lagopus) and Gyrfalcon (F. rusticolus) breeding populations experienced several declines and increases during the Peregrine Falcon recovery. Serial correlation analysis does not indicate consistent regularity in fluctuation for either the Rough-legged Hawk or Gyrfalcon on the Colville River during 1967–1985. Possible occurrence of regular fluctuations in sub-populations or over shorter time periods, however, could not be investigated. Population fluctuations for the Rough-legged Hawk and Gyrfalcon are significantly correlated during 1971–1985, with largest declines for both occurring synchronously. This correlation is consistent with the possibility that shared environmental stresses, among other factors, are responsible for population limitation. Regularity, with a 3 year interval, is indicated, however, for extremely small fluctuations in an Idaho, USA population of the Red-tailed Hawk (Buteo jamaicensis), suggesting that investigations of raptor population fluctuation and regelarity should not be limited to arctic or subarctic environments. Low diversity in food habits is not a good predictor of degree of annual population fluctuation in the study groups, while greater diversity in food habits is associated with relatively stable annual populations. An association was found in the Rought-legged Hawk between reduced annual population variability and reduced climatic severity. Neither food habits diversity nor annual population variability is constant across species ranges. Food habits diversity was also variable between years in local populations of Peregrine Falcon, Rough-legged Hawk and Gyrfalcon.

NESTING SUCCESS AND PREY SELECTION OF LONG-EARED OWLS ALONG A JUNIPER/SAGEBRUSH ECOTONE IN SOUTHCENTRAL IDAHO

During the course of a biosystematic study of the Peregrine Falcon (Falco peregrinus) by White over the past few years, observations have been made on several species of North American falcons. While all three large species (Prairie Falcon, Falco mexicanus; Gyrfalcon, Falco rusticolus; and Peregrine) have been subjected to detailed study by various writers, a few additional notes on their biology are reported herein. We would like to acknowledge the help in the field of William Tilton, Anchorage, Alaska, and the late Gary D. Lloyd of the University of Utah for stimulating discussions of the data presented. Marvin R. Meyer, of Salt Lake City, provided some data on Prairie Falcons.

Sexually mosaic plumage in a female American Kestrel

A population of Long-eared Owls (Asio otus) nesting in a juniper/sage- brush ecotone had an average density of one pair per 0.65 km2 and fledged an average of 3.7 young per nest. All 24 nests were built by corvids and were located in juniper trees. Mammals comprised 95.2% of 1000 prey remains collected. The proportion of Heteromyidae and Cricetidae taken as prey by Long-eared Owls was significantly different (x2 = 27.2, 3 df, p < 0.005) from the small mammal composition of the area. Deer mice (Peromyscus maniculatus) and pocket mice (Perognathus parvus) occurred in the same relative frequencies in pellets and in trapping studies, while kangaroo rats occurred twice as often in pellets as in traps and harvest mice occurred less than half as frequently in pellets as in traps. The objective of this research was to determine nesting density, productivity, and prey utilization of Long-eared Owls (Asio otus) nesting along a juniper (Juniperus osteo- sperma)/sagebrush (Artemisia tridentata) ecotone in southcentral Idaho. This habitat is common throughout much of the West and is an important breeding area for many raptors because of the proximity of suitable nesting sites to hunting areas. Long-eared Owls are well-suited to this habitat since they hunt in open areas (Getz 1961) and nest and roost in dense clumps of trees (Armstrong 1958, Bent 1938). Few detailed studies of Long-eared Owls have been conducted on the rangelands of western North America (Marti 1974). Studies that have been done in this region were primarily located in riparian habitat with deciduous trees or near agricultural development (Sonnenberg and Powers 1976, Craig and Trost 1979, Marks and Yensen 1980). Prior research on Long- eared Owls has not focused on use of the juniper/sagebrush ecotone, a habitat which this study shows is used extensively by this species. In fact, Long-eared Owls were the most abundant raptor in the study area where this type of habitat was present (Thurow et al. 1980).

Fluctuations of observed breeding Rough-legged Hawks and Gyrfalcons: regularity reconsidered

The plumage of the American Kestrel (Falco sparverius) is well recognized to be dichromic between the sexes (Mearns 1892, Bent 1938, Bond 1943, Friedman 1950, Parkes 1955, Cade 1982). On 24 July 1986, a female American Kestrel was found along a roadside in Salt Lake City, Utah, apparently having collided with an automobile. The right wing was missing, and the bird was emaciated and generally in poor condition. The bird was euthanized and upon examination showed both male and female plumage characteristics (Fig. 1). The breast plumage color pattern was characteristically female except for the lower left abdominal region (Fig. la), where dark brown/black spotting similar to male breast plumage pattern was present. The rectrices were most aberrant (Figs. la, b, c), and hereafter are numbered 1 (outermost) through 6 (central). Rectrix 1 right (1R) is characteristic of a typical female, except the subterminal, black band is considerably wider (Fig. Ic). Rectrix 2R is incompletely barred with black on the outer vane decreasing proximally to form tiny black spots on the margin. The inner vane contains only two partial black bars immediately proximal to a broad, subterminal black band. Rectrix 3R is incompletely barred with black on the outer vane decreasing proximally to form tiny spots as in rectrix 2R. The inner vane contains only a small black spot immediately proximal to a broad, subterminal black band, typical of males. Rectrix 4R contains no barring on either side of the vane. One small, black spot occurs on the inner vane, near the margin, and immediately proximal to a broad, subterminal black band. Rectrix 5R is virtually identical in color pattern to rectrix 4R. Rectrix 6R is incompletely barred in black on either side of the vane with the inner vane more heavily barred, but the proximal black bars do not meet at the rachis. Rectrix 6R terminates in a broad, black band, proximal to a rust colored tip. Rectrices IR to 5R are tipped in an ivory/whitish color, typical of males. Rectrices 6R, 6L, and 2L to 5L are tipped in a pale rust color, typical of females. Rectrix IL is tipped in an ivory/whitish color similar to rectrix 1R. In general, rectrices 3R, 4R, and 5R are virtually without female characteristics, with the exception of the incomplete barring on the outer vane margin of rectrix 3R. The length of the rectrices does not vary abnormally, but the vane of rectrices 2R to 5R is approximately 2 mm wider than rectrices 2L to 5L. None of the tips of the rectrices show signs of wear (Fig. Ic). Based on crown plumage characteristics (Parkes 1955) the kestrel was considered to be a hatch-year bird. The gonads were paired, not an uncommon condition that has been found in 30 to 50% of females of the genus Falco (see White 1969). The left gonad measured 1.50 x 1.00 mm and the right measured 0.66 x 0.66 mm. The right gonad was somewhat lighter in color and smoother in texture than the left, and neither was enlarged nor contained enlarged follicles. Results of a histological examination of the gonads proved inconclusive in determining whether testicular tissue was present. Visually, both gonads appeared to be ovaries.

Breeding of Say's Phoebe in Arctic Alaska

SummaryWe recently assessed regularity in fluctuation of annual numbers of breeding pairs observed for several raptor species, and found no indication of reputed regular or cyclic fluctuations in our Colville River, Alaska sample for Gyrfalcons (Falco rusticolus) or Rough-legged Hawks (Buteo lagopus) (Mindell et al. 1987). Discussions with colleagues have prompted us to expand our analysis and clarify key points. We present time series analyses, using the Colville River sample size and interval (13 surveys during a 27 year period) for a data set on lynx (Lynx canadensis) (Elton and Nicholson 1942) and for a hypothetical Gyrfalcon population. Indication of regular 10-year fluctuations (P<0.05) in these analyses supports the adequacy of our Colville River sample size and interval in assessing a possible 10-year cycle for Gyrfalcons. We provide dates and methods used for the annual Colville River surveys in discussing applications and limitations of the survey findings. We use the annual Colville River surveys as an index of fluctuation in actual numbers of Gyrfalcons and Rough-legged Hawks present in the study area at the time, based on similarity in timing of surveys between years, use of boat surveys in 12 of 13 years, evidence indicating similarity in sampling error between years, and demonstration of the adequacy of the sample interval. Whether or not numbers of breeding Gyrfalcons and Rough-legged Hawks fluctuate regularly remains an open question. We have provided a first assessment of regularity in fluctuation of observed numbers of breeding pairs, and find regularity for this parameter unsupported considering the Colville River study area as a whole. If other researchersare stirred to test “conventional wisdom” presuming regularity, our study will have served its purpose.