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Behavior and Ethology

University of Nebraska - Lincoln

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Articles 631 - 660 of 680

Full-Text Articles in Animal Sciences

Whooping Cranes At The San Antonio Zoo, Jacqueline A. Lauver Jan 1992

Whooping Cranes At The San Antonio Zoo, Jacqueline A. Lauver

Proceedings of the North American Crane Workshop

Since April, 1956, when an injured whooping crane (Grus americana) was received for rehabilitation, the San Antonio Zoo has maintained these birds in the collection and is 1 of only 2 zoos to have raised them. The zoo's management efforts, combined with favorable climatic cbnditions and water sources have contributed to a successful breeding program. The whooping crane is 1 of 7 crane species successfully bred, and 1 of 8 crane species currently in the collection.


Distribution Of Color-Marked Greater Sandhill Cranes Banded In Utah, Spyros S. Manes, Roderick C. Drewien, Joel D. Huener, Thomas W. Aldrich, Wendy M. Brown Jan 1992

Distribution Of Color-Marked Greater Sandhill Cranes Banded In Utah, Spyros S. Manes, Roderick C. Drewien, Joel D. Huener, Thomas W. Aldrich, Wendy M. Brown

Proceedings of the North American Crane Workshop

Twenty-eight greater sandhill cranes (Grus canadensis tabida) were banded and color-marked on nesting grounds in northern and central Utah during summers 1986 and 1987. Sixteen were observed 1 or more times between October 1986 and February 1988 on migration, winter and summer areas. Marking studies showed that cranes nesting east and southeast of the Great Salt Lake in northern and central Utah are affiliated with the Rocky Mountain population, with most individuals migrating during the spring and fall through the San Luis Valley, Colorado and wintering in southcentral and southwestern New Mexico, southeastern Arizona and possibly northern Mexico. …


An Evaluation Of Three Areas For Potential Populatons Of Whooping Cranes, Janet L. Mcmillen, Stephen A. Nesbitt, Mary A. Bishop, Alan J. Bennett, Laurel A. Bennett Jan 1992

An Evaluation Of Three Areas For Potential Populatons Of Whooping Cranes, Janet L. Mcmillen, Stephen A. Nesbitt, Mary A. Bishop, Alan J. Bennett, Laurel A. Bennett

Proceedings of the North American Crane Workshop

Sandhill crane (Grus canadensis) populations were evaluated on the Seney NWR, Michigan, the Okefenokee Swamp, Georgia, and in southcentral Florida to evaluate their suitability to support introduced whooping cranes (G. americana). This paper compares data collected at these sites and additional data collected in northcentral Florida. The length of the egg-laying period varied from 4.5 months in central Florida to 1 month at Seney, but egg-laying ceased at all sites from mid-May to early June. Mean clutch sizes were similar 0.7-1.9). Renesting ranged from 79% in northcentral Florida to <=5% at Seney. These dates and values are consistent with nesting successes that ranged from 48% in northcentral Florida to 80% at Seney. Average annual recruitment, 12.3 juveniles/lOa adults, was highest on the Kissimmee Prairie in southcentral Florida. Average annual horne range size for the non-migratory populations were 1 km2 on the Okefenokee and 6.6 km2 on the Kissimmee. Nesting season horne range sizes ranged from 0.5 km2 on the Okefenokee to 1.8 km2 at Seney. All candidate populations successfully satisfied most of the guidelines for potential whooping crane populations as established by the Whooping Crane Recovery Team. Once reintroduction techniques have been refined, any or all of the study sites have the capacity to accommodate a flock of whooping cranes commensurate with Whooping Crane Recovery Team recommendations.


Distribution And Status Of Greater Sandhill Cranes In Nevada, Marcus S. Rawling Jan 1992

Distribution And Status Of Greater Sandhill Cranes In Nevada, Marcus S. Rawling

Proceedings of the North American Crane Workshop

Nesting habitat of the Lower Colorado River Valley Population (LCRVP) of greater sandhill cranes (Grus canadensis tabida) was censused in northeastern Nevada from 1983 through 1986. Ninety-two nesting pairs and 594 cranes were located. Eighty-two percent were observed in central Elko County. Cranes were marked from 2 summer range locations and from the Lund, Nevada traditional spring migration stopover with patagial streamers. Cranes marked on summer range wintered on the lower Colorado River, in the Imperial Valley near Brawley, California and on the Gila River in southwestern Arizona. Cranes marked at the stopover were observed on summer range …


An Individualized Marking Scheme For Sandhill Cranes And Its Use To Determine Fall Migration Interval, Stephen A. Nesbitt, Robin D. Bjork, Kathleen S. Williams, Stephen T. Schwikert, Anne S. Wenner Jan 1992

An Individualized Marking Scheme For Sandhill Cranes And Its Use To Determine Fall Migration Interval, Stephen A. Nesbitt, Robin D. Bjork, Kathleen S. Williams, Stephen T. Schwikert, Anne S. Wenner

Proceedings of the North American Crane Workshop

A color-band based marking scheme was used for individually marking sa ndhill cranes in Florida. The band-loss rate was 2.8% per year between 1977 and 1988. Band loss was greatest on bands placed below the ankle joint and occurred most frequently during years 2 to 5. Color-marked individuals monitored during fall migration averaged 6.2 days (r=5-13 days) between the Jasper-Pulaski Fish and Wildlife area in northwestern Indiana and winlering areas in northern Florida.


Habitat Use By Greater Sandhill Cranes In Wyoming, Mary M. Rowland, Lynn Kinter, Tim Banks, David C. Lockman Jan 1992

Habitat Use By Greater Sandhill Cranes In Wyoming, Mary M. Rowland, Lynn Kinter, Tim Banks, David C. Lockman

Proceedings of the North American Crane Workshop

Wyoming suppors approximately 20% of the Rocky Mountain population (RMP) of greater sandhill cranes (Grus canadensis tabida), as well as a number of whooping cranes (Grus americana) from the Grays Lake, Idaho flock. Cranes begin arriving on post-migration staging areas in Wyoming in mid-March and disperse to summer habitat in April or May, depending on snow cover. Fall pre-migration, staging peaks around mid-September; most cranes leave the state by 1 October. Wet meadows and gram fIelds were the major habitat types used by cranes in Wyoming 1985-1987. Use in these types ranged from 69- 100% of …


Whooping Crane Habitat Alteration Analysis At Aransas National Wildlife Refuge, Texas, C. Lee Sherrod, Richard Medina Jan 1992

Whooping Crane Habitat Alteration Analysis At Aransas National Wildlife Refuge, Texas, C. Lee Sherrod, Richard Medina

Proceedings of the North American Crane Workshop

Aquatic, wetland, and upland habitat changes were quantified within the approximate critical habitat of the endangered whooping crane (Grus americana) along the Gulf Intracoastal Waterway (GIWW) through Aransas National Wildlife Refuge and San Antonio, Bay, Texas. Study procedures employed comparative analysis of pre-GIWW (1930) and present (1986) aerial photography to provide a basis for the assessment of positive and negative impacts of the construction, operation and maintenance of the GIWW, principally on the whooping crane, but also on biota in general. Thirteen habitat mapping categories were utilized to describe an approximately 1,830 m wide corridor along the GIWW …


Nesting Of Greater Sandhill Cranes On Seney National Wildlife Refuge, Richard P. Urbanek, Theodore A. Bookhout Jan 1992

Nesting Of Greater Sandhill Cranes On Seney National Wildlife Refuge, Richard P. Urbanek, Theodore A. Bookhout

Proceedings of the North American Crane Workshop

During 1987, 59 nests of 57 pairs of greater sandhill cranes (Grus canadensis tabida) were located, mainly from the air, on or near the Seney National Wildlife Refuge, Michigan, and 52 nests were ground-checked. Nests were in available palustrine classes without tree canopies. Only 19% were in Sphagnum bogs, in which most nests from other areas of the Upper Peninsula have been found. Cattail (Typha latifolia) marshes, most prevalent in the managed area of the refuge, contabed 44% of the nests, and sedge (Carex spp.) marshes accounted for 37%. Important co-dominant plant species were …


Dispersal Of Pen-Reared Mississippi Sandhill Cranes, Phillip J. Zwank, Donna A. Dewhurst Jan 1992

Dispersal Of Pen-Reared Mississippi Sandhill Cranes, Phillip J. Zwank, Donna A. Dewhurst

Proceedings of the North American Crane Workshop

Dispersal patterns of juvenile parent-reared, captive produced Mississippi sandhill cranes (grus canadensis pulla) were monitored using radiotelemetry. Dispersal chronology and distance traveled by cranes differed among 4 releases and seemed to be influenced by rearing methods. Most cranes that had been placed in communal pens before release formed flocks when released. Cranes released without communal pen experience did not flock, but individually associated with native cranes. Nonflocking released cranes dispersed more rapidly and to a greater distance, but had lower survival.


Whooping Crane Riverine Roosting Habitat Suitability Model, Jerry W. Ziewitz Jan 1992

Whooping Crane Riverine Roosting Habitat Suitability Model, Jerry W. Ziewitz

Proceedings of the North American Crane Workshop

Water development interests on the Platte River in Nebraska and recognition of the importance of this river as migratory bird habitat have prompted studies to determine how much water is needed to maintain wildlife habitat values. The whooping crane (Grus americana) is one of many species that use the Platte. A model was developed to quantify the relationship between river discharge and roosting habitat suitability for whooping cranes, designed to accommodate the data collection and hydraulic simulation techniques of the Instream Flow Incremental Methodology. Results of the model indicate that optimum roosting habitat conditions in the Big Bend …


Marking Power Lines To Reduce Avian Collision Mortality In The San Luis Valley, Colorado, Wendy M. Brown, Roderick C. Drewien Jan 1992

Marking Power Lines To Reduce Avian Collision Mortality In The San Luis Valley, Colorado, Wendy M. Brown, Roderick C. Drewien

Proceedings of the North American Crane Workshop

We examined the effectiveness of 2 marking devices designed to increase visibility of power lines and reduce avian collision mortality during spring and fall migration periods, 1988-91, in the San Luis Valley, Colorado. Eight O.8-km segments of power line were marked with either yellow spiral vibration dampers or yellow fiberglass swinging plates and compared with 8 adjoining unmarked segments. Primary species groups studied included cranes (Grus canadensis and G. americana), Canada geese (Branta canadensis), and ducks (various Anatinae). Raptors, shorebirds, wading birds, and passerines were also monitored. Both marker types reduced avian collision mortality by …


Sandhill Crane Surveys In The Northern Interior Highlands Of Mexico, Roderick C. Drewien, Wendy M. Brown, Elwood G. Bizeau Jan 1992

Sandhill Crane Surveys In The Northern Interior Highlands Of Mexico, Roderick C. Drewien, Wendy M. Brown, Elwood G. Bizeau

Proceedings of the North American Crane Workshop

Most sandhill cranes (Grus canadensis) wintering in Mexico are found in the northern Interior Highlands of Chihuahua. We surveyed sandhill cranes in the states of Chihuahua and occasionally Durango, Mexico, in winters 1972-90. The population averaged 23,106 (SD = 10,369) in 11 counts at 5-6 areas in Chihuahua. Laguna de Babicora, the most important wetland for cranes wintering in Mexico, had the largest numbers (X = 16,012), followed by Ascension (x = 2,405) and Laguna de los Mexicanos (x = 1,468). All 3 migratory subspecies were present. The lesser subspecies (G. c. canadensis) comprised 85.7% of …


Contaminants In Habitat, Tissues, And Eggs Of Whooping Cranes, James C. Lewis, Roderick C. Drewien, Ernie Kuyt, Charles Sanchez Jr. Jan 1992

Contaminants In Habitat, Tissues, And Eggs Of Whooping Cranes, James C. Lewis, Roderick C. Drewien, Ernie Kuyt, Charles Sanchez Jr.

Proceedings of the North American Crane Workshop

Sampling of contaminants in the principal habitat areas of whooping cranes (Grus americana) of both the Rocky Mountain and the Aransas/Wood Buffalo National Park whooping crane populations began in the mid-1980's. Contaminants in eggs and tissues of whooping cranes were sampled opportunistically since the 1960's. Chlorinated hydrocarbons existed in low levels in the environment. Some trace elements including aluminum, arsenic, cadmium, chromium, copper. mercury, selenium, and zinc are of sufficient abundance to justify continued monitoring. Declines over time in residues of DDT and mercury in tissues and eggs reflected the prohibition in use of these as pesticides or …


Using National Wetlands Inventory Maps To Quantify Whooping Crane Stopover Habitat In Oklahoma, Dale W. Stahlecker Jan 1992

Using National Wetlands Inventory Maps To Quantify Whooping Crane Stopover Habitat In Oklahoma, Dale W. Stahlecker

Proceedings of the North American Crane Workshop

Three stratified random samples of the 416 National Wetland Inventory (NWI) maps within the western Oklahoma portion of the Wood Buffalo-Aransas whooping crane (Grus americana) migration corridor were used to evaluate the availability of wetland roost sites. Wetlands were eliminated as potential roosts if visibility was obscured by vegetation or slope, or if certain human activities occurred within 100-800 m. Thirty percent of all wetlands >0.04 ha passed map review, but only 7% passed when ground truthed. NWI map review was a poor predictor of suitability (33 % correct) but a good predictor of unsuitability (97 % correct). …


Behavior Of Whooping Cranes During Initiation Of Migration, Thomas V. Stehn Jan 1992

Behavior Of Whooping Cranes During Initiation Of Migration, Thomas V. Stehn

Proceedings of the North American Crane Workshop

Whooping cranes (Grus americana) observed immediately before the initiation of migratory flights exhibited increased alertness, wing ruffling, and head tilting. Seven observations at Aransas National Wildlife Refuge (NWR), Texas, indicate that the departure of 1 group of whooping cranes may influence other nearby cranes to start migration, even though later departing groups may fly separately.


Development Of An Isolation-Rearing/Gentle Release Procedure For Reintroducing Migratory Cranes, Richard P. Urbanek, Theodore A. Bookhout Jan 1992

Development Of An Isolation-Rearing/Gentle Release Procedure For Reintroducing Migratory Cranes, Richard P. Urbanek, Theodore A. Bookhout

Proceedings of the North American Crane Workshop

During 1988 -90, in an effort to develop a reintroduction technique for the whooping crane (Grus americana), we reared 38 greater sandhill crane chicks (G. canadensis tabida) in isolation from humans and gentle-released them on Seney National Wildlife Refuge (NWR) in the Upper Peninsula of Michigan. Chicks were reared in the field with a puppet/costume technique. After chicks completed acclimation to wild conditions in a release pen, we induced them to migrate by breaking their flock into small groups, translocating some groups, and using guide birds. Solutions to migration initiation problems encountered in 1988-89 were developed …


Preliminary Identification Of Whooping Crane Staging Areas In Prairie Canada, Brian W. Johns Jan 1992

Preliminary Identification Of Whooping Crane Staging Areas In Prairie Canada, Brian W. Johns

Proceedings of the North American Crane Workshop

For 60 years a passive program has been in effect to monitor the migration of whooping cranes (Grus americana) through Saskatchewan, and currently the Canadian Wildlife Service coordinates a triprovincial reporting network and operates a telephone Hot Line to receive reports of sightings of migrating cranes. Analyses of historical data reported through those efforts have identified the chronology of migration, the migration corridor through Canada, and major staging/ stopover areas in Saskatchewan. Investigations are continuing to identify specific roost sites, feeding areas and the availability of suitable habitat within the staging/ stopover area.


Relationship Of Channel Maintenance Flows To Whooping Crane Use Of The Platte River, Craig A. Faanes, David B. Bowman Jan 1992

Relationship Of Channel Maintenance Flows To Whooping Crane Use Of The Platte River, Craig A. Faanes, David B. Bowman

Proceedings of the North American Crane Workshop

Periodic high flows in the Platte River are necessary to scour vegetation and redistribute sediment in the stream channel. Peak and mean annual flows have been reduced by as much as 70% from pre-development times, but channel maintenance flows still occur, although at a much reduced frequency and magnitude of occurrence. Use of the Platte River by migrant whooping cranes (Grus americana) in recent years appears to be related to the recent occurrence of flows in excess of 8,000 cfs for 5 or more consecutive days.


Lead Poisoning In A Whooping Crane, S. Bret Synder, Michael J. Richard, John P. Thilsted, Roderick C. Drewien, James C. Lewis Jan 1992

Lead Poisoning In A Whooping Crane, S. Bret Synder, Michael J. Richard, John P. Thilsted, Roderick C. Drewien, James C. Lewis

Proceedings of the North American Crane Workshop

The first known incident of lead poisoning in a whooping crane (Grus americana) occurred as the affected bird completed its second migration from Grays Lake National Wildlife Refuge (NWR), Idaho to Bosque del Apache NWR, New Mexico. It fell ill about 4 1/2 weeks after reaching the winter site and was captured. The bird exhibited signs of anorexia and starvation, weakness with drooped wings, greenish watery diarrhea and an unusual gaping of the mouth with abnormal swallowing motions. Blood showed marked polychromasia (>50%) and reticulocytosis (>80%) of RBC's. Serum chemistry values were not diagnostic. A radiograph …


The Study Of Relatedness And Genetic Diversity In Cranes, George F. Gee, Herbert C. Dessauer, Jonathan Longmire, W. Elwood Briles, Raymond C. Simon Jan 1992

The Study Of Relatedness And Genetic Diversity In Cranes, George F. Gee, Herbert C. Dessauer, Jonathan Longmire, W. Elwood Briles, Raymond C. Simon

Proceedings of the North American Crane Workshop

The U.S. Fish and Wildlife Service (Service) is responsible for recovery of endangered species in the wild and, when necessary, maintenance in captivity. These programs provide an immediate measure of insurance against extinction. A prerequisite inherent in all of these programs is the preservation of enough genetic diversity to maintain a viable population and to maintain the capacity of the population to respond to change. Measures of genetic diversity examine polymorphic genes that are not influenced by selection pressures. Examples of these techniques and those used to determine relatedness are discussed. Studies of genetic diversity, electrophoresis of blood proteins, relatedness, …


Introgression Of Coyote Mitochondrial Dna Into Sympatric North American Gray Wolf Populations, Niles Lehman, Andrew Eisenhawer, Kimberly Hansen, L. David Mech, Rolf O. Peterson, Peter J. P. Gogan, Robert K. Wayne Jan 1991

Introgression Of Coyote Mitochondrial Dna Into Sympatric North American Gray Wolf Populations, Niles Lehman, Andrew Eisenhawer, Kimberly Hansen, L. David Mech, Rolf O. Peterson, Peter J. P. Gogan, Robert K. Wayne

USGS Northern Prairie Wildlife Research Center

Mitochondrial DNA (mtDNA) genotypes of gray wolves and coyotes from localities throughout North America were determined using restriction fragment length polymorphisms. Of the 13 genotypes found among the wolves, 7 are clearly of coyote origin, indicating that genetic transfer of coyote mtDNA into wolf populations has occurred through hybridization. The transfer of mtDNA appears unidirectional from coyotes into wolves because no coyotes sampled have a wolf-derived mtDNA genotype. Wolves possessing coyote-derived genotypes are confined to a contiguous geographic region in Minnesota, Ontario, and Quebec, and the frequency of coyote- type mtDNA in these wolf populations is high (> 500%). The …


Eumeces Septentrionalis (Prairie Skink): Piscivory., Louis A. Somma Jan 1991

Eumeces Septentrionalis (Prairie Skink): Piscivory., Louis A. Somma

Papers in Herpetology

The prairie skink is a North American lizard characterized by a diet that is primarily insectivorous (Breckenridge 1943. Amer. MidI. Nat. 29:591-606). Fish have not been previously recorded as a food item (reviewed in Somma and Cochran 1989. Great Basin Nat. 49:525-534). On 3 June 1990 between 0930 and 1030 h, six Eumeces septentrionalis (three gravid females, one male, and two juveniles) were captured from amongst riprap and beneath stone slabs on the earthen dam forming the windward shoreline of Burchard lake, Pawnee Co., Nebraska (T.12N., R.10E., Sec. 4). The three females and one juvenile were placed in the …


A Report On Black-Tailed Prairie Dogs In Nebraska-- Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster Dec 1990

A Report On Black-Tailed Prairie Dogs In Nebraska-- Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster

School of Natural Resources: Dissertations, Theses, and Student Research

I examined the effects of a visual barrier fence, which had a see-through visibility of 600/0, on the foraging, vigilance, and aggressive behaviors of adult female black-tailed prairie dogs from June through August 1990 in central Nebraska. I also examined changes in their home ranges and use of an area in response to this fence. Prairie dogs prefer an open view of their surroundings. Therefore, I expected animals near a visual barrier to spend more time in vigilance and aggression, and less time foraging. Adult female prairie dogs exposed to the visual barrier devoted more time to foraging and less …


Wolf Population Survival In An Area Of High Road Density, L. David Mech Apr 1989

Wolf Population Survival In An Area Of High Road Density, L. David Mech

USGS Northern Prairie Wildlife Research Center

Wolf mortality in a high-road-density area of Minnesota exceeds that in an adjacent wilderness, and is primarily human-caused. The wolf population there is maintained primarily by ingress from the adjacent wilderness areas. A road density of 0.58 km/km2 can be exceeded and the area still support wolves if it is adjacent to extensive roadless areas.


Elaphe Bairdi (Baird’S Rat Snake): Drinking Behavior., Louis A. Somma Jan 1989

Elaphe Bairdi (Baird’S Rat Snake): Drinking Behavior., Louis A. Somma

Papers in Herpetology

On 13 February 1988. at 1600 h. a captive-bred (hatched July 1985) male Elaphe bairdi (TL.136.9 cm, SVL .. 89.54 cm). maintained in a 50.5 x 25 x 30 cm terrerium was accidently splashed with water. As beads of water on the snake's head rolled down to the upper labial sceles. swallowing was observed. The water on the labial scales was drawn Into the mouth while It was closed. This behavior lasted 42 sec. This behavior was repeated 23 out of 24 trials conducted during the next 24 days. The duration of swallowing wes 9-62 sec (avg 35.8, N = …


Survey And Reconnaissance Of Sea Turtles In The Northern Gulf Of Mexico, Larry Ogren Jan 1989

Survey And Reconnaissance Of Sea Turtles In The Northern Gulf Of Mexico, Larry Ogren

United States Department of Commerce: Staff Publications

This is a report on the results of an aerial survey of nesting beaches conducted during the period from May 16, 1977 to August 11, 1977. The area covered included the barrier beaches and offshore islands from the Florida-Alabama state line to the Rio Grande, Texas. Additional historical information is provided in order to compare current nesting activity with previous years as well as anecdotal observations on the occurrence of sea turtles in this region.


Foraging Behavior And Switching By The Grasshopper Sparrow Ammodramus Savannarum Searching For Multiple Prey In A Heterogeneous Environment, Anthony Joern Apr 1988

Foraging Behavior And Switching By The Grasshopper Sparrow Ammodramus Savannarum Searching For Multiple Prey In A Heterogeneous Environment, Anthony Joern

School of Biological Sciences: Faculty Publications

Switching among four alternative grasshopper species by the grasshop- per sparrow (Ammodramus savannarum) through frequency-dependent predation was ex- amined. Grasshoppers were presented against a heterogeneous natural background in an outdoor aviary where total density was held constant but relative density of each grasshopper species varied. Switching among prey, primarily between two of the four species, and inter-bird variability in switching was observed. Species-specific prefer- ences and interactions among the alternative grasshopper species affected the final diet choice as one grasshopper species was always preferentially selected and another disregarded independent of changes in relative density. Attributes of avian foraging behavior, including: …


Wolf Distribution And Road Density In Minnesota, L. David Mech, Steven H. Fritts, Glenn L. Radde, William J. Paul Jan 1988

Wolf Distribution And Road Density In Minnesota, L. David Mech, Steven H. Fritts, Glenn L. Radde, William J. Paul

USGS Northern Prairie Wildlife Research Center

Distribution of the wolf (Canis lupus) in parts of Wisconsin (Thiel 1985) and Michigan and Ontario (Jensen et al. 1986) has been related to the density of roads passable by 2-wheel-drive vehicles. Wolves in those regions generally do not occur where road densities exceed 0.58 km/km2, whereas similar areas nearby with fewer roads do contain wolves.

In a small segment of the wolf range in Minnesota, wolves did not have territories where roads exceeded a density of 0.73 km/km2 (T. K. Fuller, Minn. Dep. Nat. Resour., unpubl. data). In another small area of Minnesota with …


Mortality Of White-Tailed Deer In Northeastern Minnesota, Michael E. Nelson, L. David Mech Oct 1986

Mortality Of White-Tailed Deer In Northeastern Minnesota, Michael E. Nelson, L. David Mech

USGS Northern Prairie Wildlife Research Center

Abstract: Two hundred nine white-tailed deer (Odocoileus virginianus) were radiotracked in the central Superior National Forest, Minnesota, from 1973 through winter 1983-84; 85 deaths were recorded. Annual survival was 0.31 for fawns (<1.0 years old), 0.80 for yearling (1.0-2.0 years old) females, 0.41 for yearling males, 0.79 for adult (≥2.0 years old) females, and 0.47 for adult males. Monthly survival rates were high from May through December (0.94-1.00), except for yearling (0.60) and adult (0.69) bucks during the November hunting season. Most mortality occurred from January through April when gray wolf (Canis lupus) predation was an important mortality source for all cohorts. Yearlings males were most vulnerable to hunting and adult males to wolf predation.


Relationship Between Snow Depth And Gray Wolf Predation On White-Tailed Deer, Michael E. Nelson, L. David Mech Jul 1986

Relationship Between Snow Depth And Gray Wolf Predation On White-Tailed Deer, Michael E. Nelson, L. David Mech

USGS Northern Prairie Wildlife Research Center

Abstract: Survival of 203 yearling and adult white-tailed deer (Odocoileus virginianus) was monitored for 23,441 deer days from January through April 1975-85 in northeastern Minnesota. Gray wolf (Canis lupus)predation was the primary mortality cause, and from year to year during this period, the mean predation rate ranged from 0.00 to 0.29. The sum of weekly snow depths/month explained 51% of the variation in annual wolf predation rate, with the highest predation during the deepest snow.