scholarly journals A Cephalic Influence on Gastric Motility upon Seeing Food in Domestic Turkeys (Melagris gallopavo), Great-Horned Owls (Bubo virginianus) and Red-Tailed Hawks (Buteo jamaicensis)

1976 ◽  
Vol 55 (6) ◽  
pp. 2155-2165 ◽  
Author(s):  
G.E. Duke ◽  
O.A. Evanson ◽  
P.T. Redig
Keyword(s):  
Gastric Motility ◽  
Bubo Virginianus ◽  
Buteo Jamaicensis

Pharmacokinetics of butorphanol tartrate in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus)

2008 ◽  
Vol 69 (5) ◽  
pp. 596-603 ◽  
Author(s):  
Shannon M. Riggs ◽  
Michelle G. Hawkins ◽  
Arthur L. Craigmill ◽  
Philip H. Kass ◽  
Scott D. Stanley ◽  
...  
Keyword(s):  
Bubo Virginianus ◽  
Buteo Jamaicensis

Responses of Blue Jays (Cyanocitta Cristata) to Raptors that Differ in Predatory Threat

2018 ◽  
Vol 11 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Julie A. Dahl ◽  
Gary Ritchison
Keyword(s):  
Low Frequency ◽  
Peak Frequency ◽  
Cyanocitta Cristata ◽  
Bubo Virginianus ◽  
Corvus Brachyrhynchos ◽  
Buteo Jamaicensis ◽  
Accipiter Cooperii ◽  
Accipiter Striatus ◽  
Breeding Seasons ◽  
Blue Jays

Some species of birds use their vocalisations to communicate predator presence and the level of threat they pose, including two species of corvids (Corvidae), American Crows (Corvus brachyrhynchos) and Siberian Jays (Perisoreus infaustus). Our objective was to determine if Blue Jays (Cyanocitta cristata), another corvid, also use specific calls or vary the characteristics of certain calls to convey information about the level of threat posed by aerial predators. During the non-breeding seasons of 2014 and 2015, we recorded and analysed the vocal responses of Blue Jays to study skins of six species of raptors that varied in size and the level of threat they pose to Blue Jays. Experiments were conducted at seven locations in Madison County, Kentucky. The mean number of Blue Jays present during trials was 2.6, and Blue Jays uttered five different vocalisations during trials, with ditonal and monotonal jeers given most frequently. The rate at which Blue Jays uttered ditonal jeers differed among trials, with rates highest during trials with an Eastern Screech-Owl (Megascops asio) and a Sharp-shinned Hawk (Accipiter striatus). However, the characteristics of ditonal and monotonal jeers (duration, low frequency, high frequency, and peak frequency) did not differ among trials. These results suggest that Blue Jays may either perceive Eastern Screech-Owls and Sharp-shinned Hawks as the greatest threats or, alternatively, as potential, but less threatening predators, and, therefore, they were willing to take greater risks when mobbing them. In contrast, Blue Jays mobbed the other raptors, i.e. American Kestrels (Falco sparverius), Red-tailed Hawks (Buteo jamaicensis), and Great Horned Owls (Bubo virginianus), with much less intensity, likely because they posed less of a threat or, in the case of Cooper's Hawks (Accipiter cooperii) that are known predators of Blue Jays, perhaps because mobbing with greater intensity, e.g. approaching more closely, posed too great a risk. Blue Jays in our study used the same calls with the same characteristics when responding to potential predators, only calling rates differed. However, such variation in calling rates when mobbing would likely provide useful information about the presence of, and possibly the threat posed by, potential predators for conspecifics and, perhaps, heterospecifics.

The Eimeriidae (Apicomplexa) of raptors: review of the literature and description of new species of the genera Caryospora and Eimeria

1990 ◽  
Vol 68 (6) ◽  
pp. 1256-1265 ◽  
Author(s):  
Steve J. Upton ◽  
Terry W. Campbell ◽  
Maure Weigel ◽  
Richard D. McKown
Keyword(s):  
New Species ◽  
North America ◽  
Review Of The Literature ◽  
New Host ◽  
Bubo Virginianus ◽  
Buteo Jamaicensis ◽  
Strix Varia ◽  
Key Features ◽  
Buteo Swainsoni ◽  
First Time

Four new species of Coccidia (Apicomplexa: Eimeriidae) are reported from North American raptors. Caryospora kansasensis sp.nov., in the feces of Swainson's hawk, Buteo swainsoni, has ovoid oocysts which measure 37.2 × 32.6 (32.8–40.0 × 29.6–36.0) μm. Caryospora lindsayi sp.nov., from the red-tailed hawk, Buteo jamaicensis, has subspherical oocysts measuring 33.7 × 31.6 (31.2–36.0 × 30.4–32.8) μm. Eimeria megabubonis sp.nov. from the feces of the great horned owl, Bubo virginianus, has ovoid oocysts measuring 32.7 × 28.9 (28.8–36.0 × 27.2–32.0) μm. Eimeria varia sp.nov., from the barred owl, Strix varia, measures 33.1 × 30.5 (31.2 × 36.0 × 28.0–32.0) μm. In addition to the above new species, Caryospora arcayae Volcań and Medrano, 1984 is recorded for the first time from North America and is redescribed from a new host, the broad-winged hawk, Buteo platypterus. Oocysts of Caryospora uptoni and Eimeria bubonis, as well as sporocysts of Sarcocystis/Frenkelia spp., were also found. A table is provided listing key features of the known species of Caryospora and Eimeria of raptors.

scholarly journals Functional Morphology of Raptor Hindlimbs: Implications for Resource Partitioning

The Auk ◽  
2002 ◽  
Vol 119 (4) ◽  
pp. 1052-1063 ◽  
Author(s):  
Andrea B. Ward ◽  
Peter D. Weigl ◽  
Rachael M. Conroy
Keyword(s):  
Resource Partitioning ◽  
Grip Force ◽  
Prey Capture ◽  
Sympatric Species ◽  
Force Measurements ◽  
Hunting Behavior ◽  
Bubo Virginianus ◽  
Eastern Woodlands ◽  
Buteo Jamaicensis ◽  
Strix Varia

Abstract Prey capture in owls and hawks is largely dependent on the biomechanics of the hindlimbs, and both limb size and grip forces potentially determine the size of prey that can be captured and the extent of possible resource partitioning among sympatric species. Morphological study of six species of sympatric raptors—the owls Otus asio, Strix varia, and Bubo virginianus; and the hawks commonly considered their diurnal “ecological equivalents,” Falco sparverius, Buteo lineatus, and Buteo jamaicensis—revealed that, in both groups, talon closure is effected by two discrete mechanisms that function together in a potentially additive or alternative fashion. Grip force measurements obtained from live owls and hawks using “hydraulic” perches showed that grip force increases exponentially with body size and that owls produce greater forces than hawks. That finding is consistent with the distinctive osteology and myology of their hindlimbs and with their hunting behavior. These data provide some understanding of the different demands of diurnal and nocturnal hunting as well as the mechanism of coexistence for those six species in eastern woodlands.

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