Maternal defensive behavior of mountain goats against predation by golden eagles

Maternal defensive behavior against predators may appear risky but is common in many species. Herein we describe maternal defensive behavior of mountain goats ( Oreamnos americanus ) against Golden Eagle ( Aquila chrysaetos ) predatory attempts. We found that Golden Eagles attacked goats in 1.9% of sightings ( n = 311 sightings of active Golden Eagles over 12 years) but were never successful. Mothers always defended their young against Golden Eagle attacks. Predation by Golden Eagles on young-of-the-year appears low for most ungulate species, including mountain goats. The benefits of defending offspring against eagles are likely high in ungulates, and we would therefore expect selection to favor maternal defensive behavior.     

Food habits and nest characteristics of breeding raptors in southwestern Wyoming

Food habits and nest site features of the Golden Eagle ( Aquila chrysaetos ), Prairie Falcon ( Falco mexicanus ), Red-tailed Hawk ( Buteo jamaicensis ), and Ferruginous Hawk ( B. regalis ) were studied near Medicine Bow, Wyoming, during 1981 and 1982. Foods consisted primarily of leporids and sciurids. The Wyoming ground squirrel ( Spemiophilus richardsonii ) dominated the diet of Prairie Falcons, while Golden Eagles preyed on leporids more than did the other raptors. Diet overlap ranged from 59 to 99% between the species. Mean height of Golden Eagle nests was greater than nest height of other species. Most raptor nests (78%) were not visible from other active nests and were in view of roads. Prairie Falcons were the most specialized and Ferruginous Hawks the most versatile raptor species in terms of food habits and use of nest sites.     

Winter survey of raptors with notes on avian scavengers in northwestern Colorado

Winter populations of raptors and scavengers were surveyed along 175 km of rural roads in Moffat County, northwestern Colorado. The survey began in 1988 and is currently continuing. Over the 7 yr of the survey reported here, we found Golden Eagles in high abundance (￣ x = 5.8 km/eagle) compared to most studies in similar habitat. Bald Eagles were less abundant, but increasing compared to 20 yr earlier. American Rough-legged Hawks were in low abundance, probably due to the predominance of sagebrush habitat along the route. Northern Ravens were seen in low numbers in 4 yr. American Crows were seen in 2 yr. Black-billed Magpies were nearly as abundant (￣ x = 6.5 km/magpie) as Golden Eagles and often scavenged with them. Magpie and Golden Eagle numbers were significantly correlated over the years of study. We conclude that northwestern Colorado is a significant overwintering area for Golden Eagles.     

Fishes of Bly Tunnel, Lassen County, California

Leon Bly Tunnel, which connects Eagle Lake to Willow Creek, was investigated to see if the water issuing from the tunnel was lake water or spring water and to check reports of its being inhabited by fish. We found that the water was similar to that of highly alkaline Eagle Lake, despite a block placed in the tunnel in 1986. Five species of fish were found in the tunnel, the same species inhabiting both Willow Creek and Eagle Lake, although the creek was much warmer and less alkaline than the lake. The fish originated from the creek. Fish in the tunnel were either not feeding or were consuming snails ( Vorticifex sp.), the principal invertebrate present. The largest fish (35 cm SL) captured were rainbow trout ( Oncorhynchus mykiss ).     

Breeding populations of Swainson's Hawks, Red-Tailed Hawks, and Golden Eagles in north central Oregon: 1975-1982 and 1999

Populations of breeding Swainson's Hawks ( Buteo swainsoni ), Red-tailed Hawks ( B. jamaicensis ), and Golden Eagles ( Aquila chrysaetos ) present in 1999 were compared with populations present between 1975 and 1982 at a 129-km 2 site in north central Oregon. Populations of Red-tailed Hawks and Golden Eagles remained unchanged, but the number of Swainson's Hawks pairs increased from 15 to 17. In 1999 Golden Eagles used nests occupied between 1975 and 1982, and 7 of 31 pairs of Red-tailed Hawks used nests occupied in earlier years. No Swainson's Hawks nested in trees occupied earlier. Few changes in territorial boundaries were detected.     

Predatory bird populations in the east Mojave Desert, California

We surveyed 7 species of predatory birds weekly during a 12-month period (December 1992 through November 1993) in the east Mojave Desert, California. The Common Raven ( Corvus corax ) was the most frequently observed species with an average of 6.9 sightings per 100 km. Turkey Vultures ( Cathartes aura ), Red-tailed Hawks ( Buteo jamaicensis ), Loggerhead Shrikes ( Lanius ludovicianus ), American Kestrels ( Falco sparverius ), Golden Eagles ( Aquila chrysaetos ), and Prairie Falcons ( Falco mexicanus ) were seen in decreasing order of frequency of observation through the study period. Ravens, Red-tailed Hawks, Loggerhead Shrikes, American Kestrels, and Prairie Falcons were seen throughout the year. Turkey Vultures were not present during winter months, while Golden Eagles were seen only during November and December. Turkey Vultures, Red-tailed Hawks, and ravens were most numerous on agricultural lands, while Loggerhead Shrikes were most common at urban areas. Raven numbers increased with increasing number of linear rights-of-way parallel to the survey route. Perching was the most common behavior type, although Turkey Vultures and ravens were often observed soaring, flying, or standing on the ground near highways. Transmission powerline towers and telephone poles were used as perch sites disproportionately to availability.     

The breeding system of an endangered pupfish ( Cyprinodon elegans )

We examined the breeding behavior of the endangered Comanche Springs pupfish ( Cyprinodon elegans ) during 3 separate breeding seasons in a pool of springwater originating in Phantom Cave, near Balmorhea State Park, Texas, in relation to behaviors reported for the species in swift-flowing canals (Itzkowitz 1969). In the quiet pool, unlike in swift water, the breeding system was characterized by 3 different male mating tactics: territorial defense, satellite positioning, and sneak spawning. Although the breeding strategies adopted by the males were conditional, mating tactics generally reflected male size. Territorial residents were the largest, satellites were medium-sized, and sneakers were the smallest adult males observed in the population. Territorial males traversed the least amount of area, defending compact territories, while satellites and sneakers covered more area in attempts to spawn. Although preferred territories in swift water centered on algal mats, territorial residents in quiet water seemed to prefer territories around large rocks. Males defending rocks had higher reproductive successes than males occupying other substrate types. The flexibility of the males' tactics was exhibited during one year of study when large males appeared to be absent from the population. During that year, medium-sized males switched from the satellite to territorial tactic, while small males remained sneakers.     

Male size and territoriality in the cicada killer wasp Sphecius speciosus (Hymenoptera: Crabronidae)

Males of the eastern cicada killer wasp, Sphecius speciosus, occupy territories in which they may hover or where they may perch either in trees near one or more emergence holes or on the ground at these spots from which females may emerge. Large males are more likely to hold and defend these territories at a site in northern Virginia. When resident males were captured, held and weighed, the males that replaced them, which were also captured, held and weighed, had significantly lower body weights on average than the residents.     

Natural history of Phyllomedusa megacephala (Miranda-Ribeiro, 1926) (Anura: Hylidae) in southeastern Brazil,with descriptions of its breeding biology and male territorial behaviour

The breeding biology and male territorial behaviour of the large-headed leaf-frog (Phyllomedusa megacephala) were studied in three temporary altitudinal streams located in the Cerrado biome of southeastern Brazil, during three consecutive years (2007–2009). Phyllomedusa megacephala showed significant sexual dimorphism, with females being bigger and heavier than males. Acoustic and physical interactions between males defending or not defending territories including amplectant and non-amplectant males, patrolling behaviour by males without established territories, and triple amplexus were observed. Neither males nor females were observed using visual cues when searching for mates. We found that males that were present at breeding sites in previous years bred more successfully and maintained territory better.     

Vocalization and territorial behaviour of Phyllomedusa nordestina Caramaschi, 2006 (Anura: Hylidae) from southern Bahia,Brazil

Territoriality is common among amphibians with a prolonged breeding season and can be expressed through the defence of territories with vocalizations and aggressive interactions. The present study aims to describe the territorial behaviour of male Phyllomedusa nordestina, test whether the physical characteristics of males influence the results of disputes, and describe the vocalizations of the species. The study was conducted at temporary and permanent ponds located in the Ecological Reserve Michelin, Igrapiúna, Bahia, Brazil. Male P. nordestina defended territories and showed aggressive behaviour, consisting of vocal disputes, chasing and physical fighting. Winners were not bigger, heavier, or in better condition than the losers. The victory may be associated with the vocalization activity. Three types of vocalizations were recorded: the advertisement call, composed of one or two multipulsed notes, and two types of territorial calls. We also report on male patrolling behaviour and habitat use.     

Raptors of the Uinta National Forest, Utah

The past and present use of the Uinta National Forest by birds of prey was determined from historical records and surveys conducted during 1973, 1974, and 1975. Data describing the history, present status, and physical characteristics of each nest site were collected, along with the type and intensivity of human activity within a half - mile radius of the nest. In addition, limited data on fall migration of raptors along the Wasatch Front and the food habits of Golden Eagles are presented. Management guidelines, based on the results of this study, are proposed.     

Nesting territory characteristics of a migratory South American forest hawk,the White-throated Hawk (Buteo albigula) (Aves: Accipitridae), in temperate rainforest remnants of Araucanía,southern Chile

During four successive breeding periods (2007–11) we characterized the nesting territories of the white-throated hawk (Buteo albigula) in southern Chile. Territories were located in mountainous areas with mature native forest (n = 17) or mature pine plantations (n = 1). Most of the territories were distant from urban centres (>2 km). Only one or two adult hawks and one young per pair/year were observed in each territory. All nest sites were located in the upper parts of ravines. Nests were built on large, living mature trees. Platforms were bulky (>50 cm diameter) and oval or round. Eggs were white and subelliptical in shape (40.0 × 50.0 mm). Hawk pairs reproduced asynchronically extending the reproductive period for 6 months. Although some white-throated hawk pairs were tolerant of human-modified habitats, it is possible that decline in forest cover represents a potential threat for the population viability of this migratory forest hawk.     

Cladocera and Copepoda of Shokalsky Island: new data from northwest Siberia

Information on the freshwater fauna of the remote Arctic territories is very patchy, and most of the isolated islands of the Arctic Ocean remain absolutely unexplored. The pioneer data on the species composition of microcrustaceans of Shokalsky Island (northwest Siberia, Russia) is reported here. The initial three-year research revealed a total of 31 new for the area species of Cladocera and Copepoda, including new records for the whole of northwestern Siberia. Comparing the interannual differences in faunal composition, we suggested the hypothesis of the existence of a cryptic pool of species’ resting stages, which can invade the community in the event of favourable environmental conditions in the Arctic freshwaters. We also compiled all the available data from different parts of northern Siberia and compared them with the fauna of Shokalsky Island to analyse the connection between the diversity and distributional patterns of copepods and cladoceran species and the climate conditions of different territories.     

Response of wintering buteos to plague epizootics in prairie dogs

Several species of raptors winter at Rocky Mountain Arsenal National Wildlife Refuge (Refuge) including the Bald Eagle ( Haliaeetus leucocephalus ), Ferruginous Hawk ( Buteo regalis ), Red-tailed Hawk ( Buteo jamaicensis ), and Rough-legged Hawk ( Buteo lagopus ). Raptors were monitored each winter from 1988-89 to 1996-97 using a standardized road survey. Black-tailed prairie dogs ( Cynomys ludovicianus ) form a major component of the prey base for wintering raptors on the Refuge, with 1850 ha of active prairie dog towns mapped in 1988. Prairie dog town areas and population data were determined by mapping active towns and conducting visual counts on study plots to determine population density on an annual basis from 1988 to 1996. Large-scale plague epizootics were documented on the Refuge in 1988-89 and 1994-95, reducing prairie dog towns by 95% and 99%, respectively. A significant relationship was found in the numeric response of Ferruginous Hawks to changes in prairie dog town area ( r 2 = 0.96, P r 2 = 0.97, P r 2 = 0.07, P = 0.486). This contrasted sharply with the responses to prairie dog town area found for Red-tailed ( r 2 = 0.11, P = 0.377) and Roughlegged Hawks ( r 2 = 0.04, P = 0.612).     

Population dynamics of the Ferruginous Hawk during a prey decline

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Successful nesting by a Bald Eagle pair in prairie grasslands of the Texas Panhandle

We observed a breeding Bald Eagle ( Haliaeetus leucocephalus ) pair nesting in a short-grass prairie and agricultural community on the southern Great Plains of the Texas Panhandle in 2004 and 2005. The nesting eagles produced 1 fledgling in 2004 and 2 fledglings in 2005. Our assessment of landcover types within a 5-km radius of the nest indicated that grasslands accounted for most of the area (90%), followed by agricultural lands (8%). Black-tailed prairie dog ( Cynomys ludovicianus ) colonies occupied 2.5% of the area, and single human residences with associated structures (i.e., barns) occupied 2.5 ha in surface area was 51 km from the nest. An analysis of regurgitated castings collected near the nest revealed a mammalian-dominated, breeding-season diet with black-tailed prairie dogs occurring in 80.9% of the castings. Other identified prey included cottontails ( Sylvilagus spp., 15.9%), black-tailed jackrabbits ( Lepus californicus , 3.2%), pronghorn ( Antilocapra americana , 3.2%), and plains pocket gopher ( Geomys bursarius , 1.6%). Bird remains were also present in 34.9% of the castings. This is the first reported successful nesting of Bald Eagles in the panhandle region of Texas since 1916; the nest is particularly unique because of its distance from any substantial body of water.     

Brood-rearing habitat use by Rio Grande Wild Turkeys in Oregon

Wild turkey ( Meleagris gallopavo ) brood-rearing sites have been described for portions of their range, but brood-rearing habitat use and characteristics of brood-rearing sites used by Rio Grande Wild Turkeys ( M. g. intermedia ) in the Pacific Northwest were unknown. We described cover types at 362 brood-rearing sites and measured habitat characteristics at 64 of these sites used by a recently established Rio Grande Wild Turkey population in southwestern Oregon during May-September 1989 and 1990. Hens with broods used 9 of 10 available cover types. Meadows, mixed hardwood/conifer woodlands, and savannas were used more often than expected (47% of observations, P ≤ 0.05). Broods used mature mixed conifer and dense sapling/pole mixed conifer cover types less than expected and did not use brush-fields. Many brood-rearing sites were characterized by a parklike appearance. Understory vegetation averaged P ≤ 0.05). We suggest that land managers maintain mixed hardwood/conifer woodland and savanna cover types adjacent to meadows on south slopes to provide brood-rearing habitat for Rio Grande Wild Turkeys in southwestern Oregon.     

Winter habitat-use pattern of elk, mule deer, and mosse in southwestern Wyoming

Habitat-use patterns of mule deer, elk, and moose were determined on two winter range near Kemmerer, Wyoming. Mule deer used areas with the least snow depth and dominated by sagebrush. Elk were located more often than expected on wind-swept hills but used sagebrush communities more frequently as snow depths increased. Moose were generally found associated with broad, riparian zones. All three species occasionally used the same area but differed in their use of specific vegetation types and topography.