Nest success and productivity of Ferruginous Hawks in northern Montana

1997 ◽  
Vol 75 (7) ◽  
pp. 1035-1041 ◽  
Author(s):  
James R. Zelenak ◽  
Jay J. Rotella
Keyword(s):  
Multivariate Analysis ◽  
Nest Success ◽  
Ground Squirrels ◽  
North Central ◽  
Future Studies ◽  
Spermophilus Richardsonii ◽  
Moderate Sample Size ◽  
Buteo Regalis ◽  
Occupied Territories ◽  
Central Montana

In 1993–1994, we investigated nest success and productivity of Ferruginous Hawks (Buteo regalis) in north-central Montana. The 171-km2 study area contained a variety of habitats, a high density of breeding raptors, and 24 occupied Ferruginous Hawk territories. Only 42% of occupied nests produced fledglings. Occupied territories produced an average of 0.96 fledglings (SE = 0.19). Successful nests produced an average of 2.30 fledglings (SE = 0.21, n = 20). Lagomorphs were scarce on the area. Richardson's ground squirrels (Spermophilus richardsonii) were more numerous along the edges of cropfields and roads than in grasslands. Multiple regression indicated that Ferruginous Hawk nests closer to cropfields and roads and farther from other breeding raptors produced more young than other nests. Thus, habitats altered by humans, which were not extensive (20% cultivated), apparently had higher densities of ground squirrels and thereby benefited breeding hawks. However, because our multivariate analysis was exploratory and based on a moderate sample size, our results should be interpreted cautiously and further evaluated in future studies.

Isotaphonomy in concept and practice: an exploration of vertebrate microfossil bonebeds in the Upper Cretaceous (Campanian) Judith River Formation, north-central Montana

Paleobiology ◽  
2017 ◽  
Vol 43 (2) ◽  
pp. 248-273 ◽  
Author(s):  
Raymond R. Rogers ◽  
Matthew T. Carrano ◽  
Kristina A. Curry Rogers ◽  
Magaly Perez ◽  
Anik K. Regan
Keyword(s):  
Upper Cretaceous ◽  
Statistical Tests ◽  
Sampling Strategies ◽  
North Central ◽  
Wetland Ecosystems ◽  
Future Studies ◽  
Size And Shape ◽  
Definition Of ◽  
Central Montana ◽  
Judith River Formation

AbstractVertebrate microfossil bonebeds (VMBs)—localized concentrations of small resilient vertebrate hard parts—are commonly studied to recover otherwise rarely found small-bodied taxa, and to document relative taxonomic abundance and species richness in ancient vertebrate communities. Analyses of taphonomic comparability among VMBs have often found significant differences in size and shape distributions, and thus considered them to be non-isotaphonomic. Such outcomes of “strict” statistical tests of isotaphonomy suggest discouraging limits on the potential for broad, comparative paleoecological reconstruction using VMBs. Yet it is not surprising that sensitive statistical tests highlight variations among VMB sites, especially given the general lack of clarity with regard to the definition of “strict” isotaphonomic comparability. We rigorously sampled and compared six VMB localities representing two distinct paleoenvironments (channel and pond/lake) of the Upper Cretaceous Judith River Formation to evaluate biases related to sampling strategies and depositional context. Few defining distinctions in bioclast size and shape are evident in surface collections, and most site-to-site comparisons of sieved collections are indistinguishable (p≤0.003). These results provide a strong case for taphonomic equivalence among the majority of Judith River VMBs, and bode well for future studies of paleoecology, particularly in relation to investigations of faunal membership and community structure in Late Cretaceous wetland ecosystems. The taphonomic comparability of pond/lake and channel-hosted VMBs in the Judith River Formation is also consistent with a formative model that contends that channel-hosted VMBs were reworked from pre-existing pond/lake assemblages, and thus share taphonomic history.

Populations of ferruginous and Swainson's hawks increase in synchrony with ground squirrels

1989 ◽  
Vol 67 (10) ◽  
pp. 2596-2601 ◽  
Author(s):  
Josef K. Schmutz ◽  
Daniel J. Hungle
Keyword(s):  
Ground Squirrel ◽  
Prey Density ◽  
Prey Species ◽  
Ground Squirrels ◽  
Crop Damage ◽  
Agricultural Fields ◽  
Fledging Success ◽  
Spermophilus Richardsonii ◽  
Buteo Regalis ◽  
Buteo Swainsoni

We compared changes in the densities of breeding ferruginous (Buteo regalis) and Swainson's hawks (Buteo swainsoni) over a period of 9 years with the abundance of a major prey species, Richardson's ground squirrel (Spermophilus richardsonii). We used the amount of poison distributed by landowners annually in their attempts to reduce crop damage by ground squirrels as an index of ground squirrel abundance. Though ground squirrel abundance was positively correlated with hawk density overall, the hawks differed in their responses to changing prey density. Breeding density and fledging success of the ferruginous hawk, a food specialist, were consistently correlated with squirrel abundance. The density of Swainson's hawks increased only where grassland was interspersed with agricultural fields. Fledging success of Swainson's hawks was not correlated with ground squirrel abundance. We suggest that the availability of small prey in spring affected breeding dispersion and reproductive success of Swainson's hawks.

Dwarf Shrew (Sorex nanus) in North-Central Montana

1977 ◽  
Vol 58 (2) ◽  
pp. 248-250 ◽  
Author(s):  
L. S. Thompson
Keyword(s):  
North Central ◽  
Central Montana

Evidence for Picea pungens in north-central Montana and its significance

1978 ◽  
Vol 56 (9) ◽  
pp. 1118-1121 ◽  
Author(s):  
W. L. Strong
Keyword(s):  
Native Species ◽  
The State ◽  
Geographical Range ◽  
North Central ◽  
Picea Pungens ◽  
Central Montana

The analysis of Picea cone scales from the Sweetgrass Hills of Montana substantiates the existence of Picea pungens Engelm. in north-central Montana. These results extend the geographical range of P. pungens and identify a new native species within the state of Montana.

Effects of central injection of biogenic amines during arousal from hibernation

1979 ◽  
Vol 236 (3) ◽  
pp. R162-R167 ◽  
Author(s):  
J. D. Glass ◽  
L. C. Wang
Keyword(s):  
Ambient Temperature ◽  
Specific Heat ◽  
Biogenic Amines ◽  
Heat Production ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
Simultaneous Measurements ◽  
Apparent Specific Heat ◽  
Intracerebroventricular Injections ◽  
Made In

Simultaneous measurements of heat production (HP) and heat loss (HL) and brain and rectal temperatures were made in Richardon's ground squirrels (Spermophilus richardsonii) rewarming from hibernation at an ambient temperature of 6.0 +/- 0.5 degrees C. Calculations from HP and HL measurements from control animals showed that due to differential rewarming, there was a reduction of apparent specific heat of the animal to 0.59 cal/g. degrees C. This resulted in an energy saving of 30%. Three intracerebroventricular injections of 5-hydroxytryptamine (5-HT) of 56 microgram each at brain temperatures of 10, 20, and 30 degrees C caused initial suppression of HP and a greater overall HL, which resulted in a slower rate of arousal as compared to the controls. Injections of norepinephrine (NE) of 12.5 microgram each at similar brain temperatures caused a greater rate of HP, which resulted in a faster rate of arousal as compared to the controls. The respective actions of 5-HT and NE on thermoregulation during rewarming are similar to those in some euthermic hibernators and nonhibernating species. Our data indicated that these substances evoke thermoregulatory responses during arousal in much the same manner as during normothermia.

scholarly journals Assessment of undiscovered oil and gas resources in the North-Central Montana Province, 2017

Fact Sheet ◽  
2018 ◽  
Author(s):  
Christopher J. Schenk ◽  
Tracey J. Mercier ◽  
Michael E. Brownfield ◽  
Marilyn E. Tennyson ◽  
Cheryl A. Woodall ◽  
...  
Keyword(s):  
Oil And Gas ◽  
North Central ◽  
The North ◽  
Oil And Gas Resources ◽  
Central Montana
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