Prairie Falcon Research Articles

Prey Delivery, Caching, and Retrieval Rates in Nesting Prairie Falcons

From 1984-1987, 48 nesting attempts of Prairie Falcons (Falco mexicanus) were observed for 568 days (8,397 hr) in southwestern Idaho. Observations started 1-5 weeks prior to incubation until the young were 35 days old or a nesting attempt failed. I investigated prey delivery, caching, and retrieval rates during the nesting season; relationships between prey delivery rates, hatching date, the number of young fledged per pair, and the physical condition of the young were assessed. The main prey item was the Townsend's ground squirrel (Spermophilus townsendii), which accounted for 37% of all delivered prey items (n = 1,742 items). Males delivered 97.5, 95.3, and 70.2% of all prey items during the preincubation, incubation, and brood-rearing stages, respectively. Overall, males delivered 76.6% of all prey. Prey delivery rates by a pair were three to four times higher during brood rearing than during preincubation and incubation. The prey delivery through the day was bimodal in frequency and may have reflected the diurnal aboveground activity pattern of the falcon's main prey item, the Townsend's ground squirrel. Diurnal caching patterns followed delivery patterns. Prey delivery rates per pair/hour decreased with progressively later hatching dates, resulting in a decrease in productivity. Prey delivery rates per pair/ hour and the proportion of Townsend's ground squirrel in a falcon pair's diet increased with the number of young fledged per pair. Caching and retrieval rates peaked during the first 2 weeks of brood rearing and then declined. Retrieval rates did not differ from caching rates. Prey retrievals peaked in the early morning and late afternoon hours. Caching was considered an important behavioral mechanism to maximize food intake and to dampen fluctuations in prey availability.

Effects of Patagial Tags on Laying Date and Egg Size in Common Eiders

We examined the effects of patagial tags on common eiders (Somateria mollissima) by comparing laying date, clutch size, and egg size of the same females in 2 breeding seasons, before tagging (1987) and after the birds had carried tags for 1 year (1988). Similar data were obtained from unmarked birds used as controls in both years. Clutch size of tagged birds did not differ from controls (P > 0.05), but tagged birds laid eggs later (P < 0.001) and produced smaller eggs (P < 0.05) in 1988 than in 1987. The egg size of control females was larger (P < 0.001) during 1988. We suggest that patagial tags affect a female's ability to accumulate body reserves before breeding by decreasing feeding time, increasing preening activity, and/ or increasing energy costs of diving. J. WILDL. MANAGE. 54(2):216-218 Recognizing individual birds is necessary in behavioral studies of waterfowl. Colored leg bands are not useful because they are rarely visible. Since Anderson (1963) described patagial tags, they have been commonly used in studies of behavior and movements of individual waterfowl and other birds (Marion and Shamis 1977). The advantages of patagial tags are high visibility and long retention (Southern 1971, Marion and Shamis 1977, Kochert et al. 1983). However, several researchers reported detrimental effects of patagial tags. For example, skin and feather abrasion occurred in prairie falcons (Falco mexicanus) (Kochert et al. 1983), herring gulls (Larus argentatus) (Mudge and Fern 1978), and ring-billed gulls (L. delawarensis) (Southern 1971). In ring-billed gulls, tags also interfered with pairing, delayed arrival at the colony, and postponed hatching (Southern and Southern 1985). Mortality rates of American kestrels (Falco sparverius) (Bolen and Dreden 1980) and willets (Catoptrophorus semipalmatus) (Howe 1980) possibly increased as a result of tagging. Szymczak and Ringelman (1986) reported changes in habitat use by wing-tagged mallards (Anas platyrhynchos) that resulted in increased mortality from hunting. Patagial tags have been used in several studies of common eiders (e.g., Gorman and Milne 1972, Munro and Bedard 1977, Schmutz et al. 1982), but only Anderson (1963) reported the possible effects of these markers. We evaluated the effects of patagial tags on common eiders by comparing laying date, clutch size, and egg size of individuals in the breeding season before they were marked with that of the same birds after they had carried patagial tags for 1 year. During both seasons, we also obtained similar data on control birds, which were either legbanded or not marked at all. We thank T. B. Moum, H. S. Ludvigsen, J. H. Heggas, F. Rikardsen, and H. M. Iversen for help in the field, and D. G. Jorde, R. T. Barrett, and W. Vader for reviewing the manuscript. We also thank R. T. Barrett and J. Marks for correcting the English. Funding was by grants from the Nansen Foundation and The Wildlife Fund, Troms County (to KEE). STUDY AREA AND METHODS The fieldwork was conducted at an eider colony (about 400 breeding pairs) on Grindoya, a small island (0.65 km2) near Tromso, northern Norway (69040'N, 18015'E) in 1987 and 1988. The island is covered by a mixture of woodland (50%), heaths, bogs, and fens. The dominant tree was mountain birch (Betula pubescens) with lower canopies of common juniper (Juniperus communis), willow (Salix spp.), crowberry (Empetrum hermaphroditum), and blueberry (Vaccinium myrtillus). Egg laying started in mid-May, and most of the birds left the colony in late June. We searched the island for nests at the start of the breeding season, and we used a hand net to catch females on their nests during late incubation. In 1987, 84 females were caught and marked with numbered patagial tags and steel leg bands. Patagial tags were 0.8 x 60.0 x 40.0 mm Darvic, PVC plastic. Tags were attached using a 30-mm nylon pin through the patagial membrane and a 10-mm nylon washer in each end and were fixed in position by melting the nylon pin. Of 84 marked females, 25 were found on a

Prairie Falcon Nesting on Transmission Towers

Journal Article Prairie Falcon Nesting on Transmission Towers Get access Jerry A. Roppe, Jerry A. Roppe Environmental Services Department, Pacific Power and Light Company, Portland, OR 97204 Search for other works by this author on: Oxford Academic Google Scholar Steven M. Siegel, Steven M. Siegel Environmental Affairs, Sierra Pacific Power Company, Reno, NV 89511 Search for other works by this author on: Oxford Academic Google Scholar Steven E. Wilder Steven E. Wilder Environmental Services Department, Pacific Power and Light Company, Portland, OR 97204 Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 91, Issue 3, 1 August 1989, Pages 711–712, https://doi.org/10.2307/1368123 Published: 01 August 1989 Article history Received: 30 June 1988 Accepted: 16 February 1989 Published: 01 August 1989

Brief Observations of Peregrine and Prairie Falcon Behaviour

Brief Observations of Peregrine and Prairie Falcon Behaviour

Common Barn-Owl Killed by a Prairie Falcon

Common Barn-Owl Killed by a Prairie Falcon

Estimating Prairie Falcon and Golden Eagle Nesting Populations in North Dakota

Estimating Prairie Falcon and Golden Eagle Nesting Populations in North Dakota

Snow Buntings Feeding on Leaves of Salt-Marsh Grass during Spring Migration

rie Falcon study. North Dakota Outdoors 43(8): 14-15. DENTON, S. J. 1975. Status of Prairie Falcons breeding in Oregon. M.S. thesis, Oregon State Univ., Corvallis. EDWARDS, B. 1968. A study of the Prairie Falcon in southern Alberta. Blue Jay 26:32-37. ENDERSON, J. H. 1964. A study of the Prairie Falcon in the central Rocky Mountain region. Auk 81: 332-352. JAKES, P. J., AND W. B. SMITH. 1982. A second look at North Dakota's timberland. U.S.D.A. For. Serv. Res. Bull. NC-58., St. Paul, MN. LEEDY, R. R. 1972. The status of Prairie Falcons in western Montana: Special emphasis on possible effects of chlorinated hydrocarbon insecticides. M.Sc.thesis, Univ. Montana, Missoula. OGDEN, V. T. 1973. Nesting density and reproductive success of the Prairie Falcon (Falco mexicanus) in southwestern Idaho. M.S. thesis, Univ. Idaho, Moscow. PLATT, S. W. 1974. Breeding status and distribution of the Prairie Falcon in northern New Mexico. M.S. thesis, Oklahoma State Univ., Stillwater. PORTER, R. D., AND C. M. WHITE. 1973. The Peregrine Falcon in Utah, emphasizing ecology and competition with the Prairie Falcon. Brigham Young Univ. Sci. Bull., Biol. Ser. 18:1-74. RUNDE, D. E., AND S. A. ANDERSON. 1986. Characteristics of cliff and nest sites used by breeding Prairie Falcons. Raptor Res. 20:21-28. SNOW, C. 1974. Prairie Falcon (Falco mexicanus). Habitat Management Series for Unique or Endangered Species. Report 8. U.S. Bur. Land Manage., Denver, CO. SOKAL, R. R., AND F. J. ROHLF. 1981. Biometry: The principles and practice of statistics in biological research. 2nd ed. W. H. Freeman and Co., San Francisco. STEWART, R. E. 1975. Breeding birds of North Dakota. Tri-College Center for Environmental Studies, Fargo, ND. TYLER, J. G. 1923. Observations on the habits of the Prairie Falcon. Condor 25:90-97. WILLIAMS, R. N. 1981. Breeding ecology of Prairie Falcons at high elevations in central Colorado. M.S. thesis, Brigham Young Univ., Provo, UT. WILLIAMS, R. N. 1984. Eyrie aspect as a compensator for ambient temperature fluctuations: A preliminary investigation. Raptor Res. 18:153-155.

Prairie Falcon Aerie Site Characteristics and Aerie Use in North Dakota

Stewart (1975) believed that in North Dakota, Prairie Falcons (Falco mexicanus) were uncommon and local in the badlands and on adjacent plains along the Little Missouri and Missouri rivers. However, there have been no comprehensive studies of the species in the state. Information about aerie sites will help to identify Prairie Falcon nesting habitat and aid comparison of aerie site characteristics to those in other places.

Haematosiphon inodorus (Hemiptera: Cimicidae) in a Nest of a Bald Eagle (Haliaeetus leucocephalus) in Arizona

Haemutosiphon inodorus (Duges), the Mexican chicken bug, is a bloodsucking ectoparasite recorded from only nine species of birds of prey (Falconiformes and Strigiformes) and domestic fowl (Galliformes): California condor (Gymnogyps californiunus Shaw), turkey vulture (Cathartes aura Wied), golden eagle (Aquila chrysaetos L.), red-tailed hawk (Buteo jamaicensis Gmelin), prairie falcon (Falco mexicanus Schlegel), great horned owl (Bubo virginianus Gmelin), barn owl (Tyto alba Bonaparte), domestic chicken (Callus gallus L.), and domestic turkey (Meleagris gallopavo L.) (see Wilson and Oliver, 1978, Southwest. Nat. 23: 305307). The Mexican chicken bug is relatively uncommon in southwestern U S A . (Usinger, 1966, Monograph of Cimicidae, Horn Shafer Co., Baltimore, Maryland, 585 pp.; Lee, 1955, Pan-Pac. Entomol. 31: 137-138; Wilson and Oliver, 1978, op. cit.). The USDA Cooperative Extension Service and the Insect Identification Laboratory of the Arizona State Agriculture Commission have no reports of any serious infestations on domestic poultry in Arizona. This note documents the first recorded occurrence of H. inodorus in an active nest of a bald eagle in sufficient numbers to have caused or contributed to the death of two eaglets. The eagle nest was located in east-central Arizona in Sonoran desertscrub habi-

The Consequences of Reverse Sexual Size Dimorphism for Oxygen Consumption, Ventilation, and Water Loss in Relation to Ambient Temperature in the Prairie Falcon, Falco mexicanus

The reversed sexual size dimorphism of prairie falcons is near the extreme found among raptorial birds. Mean basal metabolic rate (BMR) for males (390.2 ± 15.0 ml O₂/h) and females (504.8 ± 23.3 ml O₂/h) and mass-specific metabolism (0.79 ± 0.05 ml O₂/g h and 0.67 ± 0.03 ml O₂/g h, respectively) differ significantly between sexes. Females have a slightly broader thermal neutral zone (TNZ) than males; the upper critical temperature ($T_{uc}$) is ∼ 35 C for both sexes, and the lower critical temperature ($T_{lc}$) is 19 and 22 C, respectively. Below the $T_{lc}$ mass-specific rate of heat loss is the same in both sexes; the males' mean mass-specific conductance is 81% of the allometrically predicted value, and the females' is 86%. Mass-specific conductance of males diminishes more than that of females as ambient temperature ($T_{a}$) decreases. Mean tidal volumes and mean minute volumes ($\dot{V}_{I}$) are smaller in males than in females, but ventilatory patterns are similar for the sexes. Mean frequency a...

A Record of Tree-Nesting Prairie Falcons in Wyoming

A Record of Tree-Nesting Prairie Falcons in Wyoming

Herpesviruses and Newcastle disease viruses in white storks (Ciconia Ciconia)

Three herpesviruses were isolated from white storks (Ciconia ciconia). All isolates reacted in cross-neutralisation tests with homologous antisera and with sera prepared against a herpesvirus from a black stork (Ciconia nigra). These data indicate serologic relatedness of the herpesviruses from both stork species. Antisera prepared against herpesviruses from the domestic chicken (viruses of Marek's disease and infectious laryngotracheitis), turkey, duck and pigeon as well as from the blue-fronted amazon (Amazona aestiva), prairie falcon (Falco mexicanus), eagle owl (Bubo bubo), Lake Victoria cormorant (Phalacrocorax melanoleucos), bobwhite quail (Colinus virginianus) and desmoiselle crane (Anthropoides virgo) did not react with the stork herpesviruses. Neutralising antibodies against stork herpesvirus were detected in the majority of 72 blood samples from white and black storks. In addition, three Newcastle disease viruses (NDV) could be isolated from white storks. One isolate was highly virulent the two others were avirulent for the chicken. Haemagglutination inhibition tests have shown that some storks have antibodies against Paramyxovirus- (PMV)-1 (NDV), PMV-2 and PMV-3. No antibodies could be detected in stork sera against PMV-4, -6 and -7.

Development versus Preservation in the Snake River Birds of Prey Conservation Area

The proposed Birds of Prey Conservation Area (BPCA) contains approximately 800,000 acres of mostly public land along the Snake River in southwestern Idaho. It is the most concentrated nesting site for birds of prey-or raptors-in North America, including prairie falcons and peregrine falcons, hawks, eagles, and owls. It also provides habitat for jackrabbits and ground squirrels, the raptors' principal prey, as well as forage for domestic livestock. In addition, the area has a potential use in irrigated agriculture. Bird protection, grazing, and irrigated agriculture came into direct conflict with each other in 1978 when the secretary of interior requested the Bureau of Land Management (BLM) to assess allocation of these acres as a reserved natural area. This conflict provided the impetus for our analysis. The federal Desert Land Act of 1877 and Carey Act of 1906 permit withdrawal of these lands from the public domain for agricultural development. Locally, withdrawal means irrigated production of primarily potatoes and sugar beets. These crops replace the natural vegetation and, therefore, compete with grazing. Irrigated agricultural development also destroys natural ground cover for rabbits and squirrels, thereby creating competition with bird protection. The result is an interesting and unusual, perhaps unique, political alliance. Raptor protectors and grazing interests are usually fierce opponents. The latter fear that the birds kill young livestock. In this case, however, the ranchers' usual opposition to the birds is subordinated to their fear of total loss. Meanwhile, their livestock keep the range vegetation short, enabling raptors to find prey more easily. As a result raptor protectors and livestock organizations readily united to confront their common opponent, irrigated agricultural development.' The analytical problem confronting BLM takes the classical form of two mutually exclusive alternatives, development (irrigated agriculture) versus preservation (grazing and raptor protection). The problem is complicated by the uncertain nature of irrigated agricultural development and by the nonmarket raptor protection values. We consider this problem, proceeding from a conceptual model to an empirical estimation to conclusions and policy implications.

Occurrence and foraging habits of Prairie Falcons, Falco mexicanus, at Beaverhil! Lake, Alberta

Occurrence and foraging habits of Prairie Falcons, Falco mexicanus, at Beaverhil! Lake, Alberta

Further records of Ornithodoros ticks on Prairie Falcons and in bat-inhabited buildings in Canada

Further records of Ornithodoros ticks on Prairie Falcons and in bat-inhabited buildings in Canada

Reproduction of Prairie Falcons by Artificial Insemination

Reproduction of Prairie Falcons by Artificial Insemination

Nest Site Selection for Prairie Falcons

Nest Site Selection for Prairie Falcons

Nesting Density and Success of Prairie Falcons in Southwestern Idaho

Nesting Density and Success of Prairie Falcons in Southwestern Idaho

Pollutant effects on the reproduction of the Prairie Falcons and Merlins of the Canadian prairies

Pollutant effects on the reproduction of the Prairie Falcons and Merlins of the Canadian prairies

Present status of the Prairie Falcon in Saskatchewan

Present status of the Prairie Falcon in Saskatchewan