Philip C. Mankin

Vulnerability of Ground Nests to Predation on an Agricultural Habitat Island in East-Central Illinois

-Predation of artificial ground nests (n = 388) was studied in 1986 and 1987 in E-central Illinois. The 61-ha study area included small tracts of old field, native and introduced grasses and cropland. Thirty-five percent of all nests were destroyed during 10day trials; 51% within the 1st 2 days. Nest predation was influenced by heterogeneity of vegetation and nest concealment. The fate of a given nest was related to the fate of nearby nests although distance to the nearest nest and nest densities were not significant factors. Distances from nests to boundaries (changes in one cover type to another) did not affect nest outcome. Nest predation was relatively low along roadsides leading away from the study area.

White-tailed Deer Dispersal Behavior in an Agricultural Environment

ABSTRACT Dispersal behavior was examined for 119 male and 102 female white-tailed deer (Odocoileus virginianus) fawns marked in central and northern Illinois. Fawn movement behavior was recorded for 35 single, 78 pair and 10 triplet litters that survived intact beyond family breakup in late spring. Males (65%) dispersed at a higher rate than females (39%). Females dispersed Apr.–Jul., while males dispersed Apr.–Jul. and Sep.–Nov. The dams and siblings movements most affected fawn movement behavior with most fawns of dispersing/migrating females and siblings leaving their natal range. As yearling-adult densities and forest cover increased on our study areas, female fawn dispersals decreased. Habitat scarcity in spring coupled with high fawn survival into the spring months promoted higher than expected female dispersal behavior. Distance traveled to a new range did not differ among study areas, years or month of dispersal for either sex. Single fawns were as likely to disperse as fawns from pairs or triplets. Control of high density deer populations will be more difficult where female dispersal is prevalent, as in the agriculturally dominated Midwest landscape.

Burrow Morphology as Related to Social Organization of Microtus ochrogaster

The underground nest and associated burrows of male-female pairs and communal, social groups of Microtus ochrogaster were compared using excavated foam-injected casts of burrows. Differences in burrow morphology were related primarily to the type of social group inhabiting the nest and not to seasonal differences. There was no relationship between the number of reproductive females in a group and the number of nest chambers in the burrow system. Burrows where communal groups nested had greater complexity than burrows of male-female pairs; communal nest chambers were 49% larger, and burrow area was 2.7 times larger, with twice as many entrance holes.

A regional model of the eastern cottontail and land-use changes in Illinois

The eastern cottontail (Sylvilagus floridanus) is important in ecological food webs as a prey species for a wide variety of predators throughout its range, and is also a popular game animal. From 1956 to 1978, the eastern cottontail is estimated to have declined at least 70% in Illinois and more than 90% in the most intensively farmed regions of the state. We describe long-term changes in the index of relative abundance for the eastern cottontail in Illinois in relation tQ regional patterns of land use. Classification and regression trees (CART) analysis was used to analyze county-level changes in 6 land-use variables (row crops, hay, diverted cropland, woodland, small grains, pasture) in relation to the number of cottontails harvested per hunter per day, 1956-69 versus 1982-89. In the early period (1956-69), 78% of the counties had an index of at least 1.50 cottontails hunter -1 . day -1 , compared to only 28% of the counties in the recent period (1982-89). The amounts of pasture, hay, and small grains were positively correlated (P ≤ 0.01) with the change in cottontail index, and 2 response regions were identified with the change in pasture. The region with the least decline in cottontail index had more pasture, hay, and woodland. The stable amount of woodland during recent decades may have moderated the decline in cottontails, despite the negative influences of the other land-use changes. Long-term changes in the cottontail index in Illinois predictably track changes in farming and geomorphic factors that modify agriculture. Our analyses underscore the influence of agriculture on upland wildlife over expansive temporal and spatial scales in North America, influences that are not necessarily apparent in finerscale studies.

Responses of Eastern Cottontails to Intensive Row-Crop Farming

We studied responses of 25 transmitter-equipped eastern cottontails ( Sylvilagus floridanus ) to intensive farming disturbances in Illinois from June 1990 to April 1993. Home ranges during the row-crop growing season (June–October) averaged 2.3 times larger than during the nongrowing season and 7–8 times larger than those reported in previous studies. There were no differences between sexes in size of home ranges or use of cover in either season. Habitat composition within home ranges of cottontails was not different than from the entire study area during the growing season. During the nongrowing season, cover type of the farmstead was a key element in home ranges of rabbits; it represented <2% of the study area but comprised 23% of home ranges and 40% of locations of rabbits. Fifty-five percent of rabbit locations during the nongrowing season were located in harvested row crop fields. Our study demonstrated how rabbits respond to spatial and temporal environmental changes caused by intensive agriculture where expansive row crops is the primary cover type.

Mammals of Illinois and the Midwest: Ecological and Conservation Issues for Human-Dominated Landscapes

In this chapter, we address how mammals have been affected by changes in midwestern landscapes over time, using Illinois as an example of extreme habitat disturbance. We will outline the key events which took place since the advent of European settlers, including an in-depth look at the last four decades, when land use changes have accelerated and anthropogenic disturbances have become even more dramatic.

Declining Survival of Ring-Necked Pheasant Chicks in Illinois during the Late 1900s

Previous studies indicated that survival of ring-necked pheasant (Phasianus colchicus) chicks during the first 6 weeks of life declined from the early 1950s through early 1980s in Illinois with the expansion of corn and soybean production and associated clean farming practices. From the early 1980s through mid-1990s intensive row-crop production was moderated by farm programs such as the Conservation Reserve Program (CRP) and annual set-aside, which diverted millions of hectares of cropland from production. We evaluated the survival of pheasant chicks in Illinois in relation to these recent land-use practices. Specifically, our objectives were to determine if there were changes in chick survival during the 1980s and 1990s, and if there wer regional differences in chick survival related to land-use practices. We observed 574 broods along transect roa routes on the Sibley Study Area (SSA) in eastcentral Illinois, and 964 broods on routes throughout the pheasant range in Illinois. In spite of the increase in potential brood habitat on set-aside farmland, chick survival remained low from 1982 to 1996. For example, there was a 5-fold increase in the amount of forage legumes and small grains on the SSA from 1987-91 compared to 1975-81, with the average number of chicks per brood at 4.3 (1987-91) and 4.2 (1975-81). For survey routes throughout the Illinois pheasant range, the number of grassy fields (primarily narrow, linear tracts) in 1990 was positively correlated (r 2 = 0.15, P < 0.02, n = 37) with chicks per brood, but this relation explained only 15% of the variation. The lack of improvement in chick survival in recent decades relates to the pervasive clean farming practices in the Illinois pheasant range. More-over, most of the set-aside land in the Illinois pheasant range was under annual contract and seeded late to monotypic oats, which is cover of marginal value to foraging pheasant chicks.

Migration Behavior among Female White-Tailed Deer in Central and Northern Illinois

ABSTRACT Thirty-nine female white-tailed deer (Odocoileus virginianus) were migrators from three study areas in central and northern Illinois, 1980–1993. Migrants averaged 21.5%, 9.4% and 14.6% of marked females known alive each year on the east-central, west-central and northern study areas, respectively. Females migrated to a summer range between late Feb. and early Jul. and to the winter range between late Sep. and early Jan. Spring migration distances averaged between 7.3 and 15.9 km from the winter range. Female fawns of migrating mothers were more likely to disperse or migrate than were fawns of sedentary mothers. Migrating females survived as long as sedentary females and significantly better than females that dispersed, but fawn recruitment was lower for migrating females compared with sedentary females. Winter severity did not affect return behavior from a summer range. Hunter harassment on the summer range initiated migration back to the winter range in 59% of 22 monitored migrations for 14 radio marked females. Prevailing winds from the winter or summer range appeared to help locate these ranges for 10 of 19 spring migrations for 16 females and three of seven fall migrations for four females. Migration behavior allows females to more fully utilize the fragmented landscapes of the agricultural Midwest. Migration behavior among females appears to result from resource competition among females including parturition sites where female densities are high and available habitats are scarce.

Disturbance and the Survival of Female Ring-Necked Pheasants in Illinois

There is little knowledge of how disturbances affect the behavior and survival of pheasants in agricultural landscapes of the Midwest. Thus, we studied the survival of 81 female ring-necked pheasants (Phasianus colchicus) in Ford County, eastcentral Illinois, from 1989-94. Among the most intensively cropped regions of North America, the study area averaged 93% row crops (corn and soybeans, in equal proportion). We monitored the numbers of extended movements by hens associated with farm operations, hunting, weather, and other causes. The average number of extended movements observed per bird (3.5 ± 0.4) was not different for adults and juveniles. Using the Kaplan-Meier product-limit estimator of survival, the longevity of hens with more than the median number of extended movements was greater (330 ± 37 days) than hens with less than the median number of extended movements (115 ± 15 days). Hens exhibiting disturbance-avoidance behavior associated with extended movements coped relatively well with hazards, except during nesting. Our findings underscore the importance of movement as a survival mechanism in a hazardous landscape with marginally suitable habitat.

Characteristics of Dominant and Subordinate Led Social Groups of White-tailed Deer in Illinois

Abstract This study of dominant and subordinate led social groups of white-tailed deer (Odocoileus virginianus) was designed to investigate longevity and associations among members as well as the reproductive success that determines the durability of these groups. Characteristics of 25 dominant and 17 subordinate female led social groups of white-tailed deer were studied on three areas in Illinois. Group size for dominant led social groups ranged between 3.8 and 5.2 deer/y and for subordinate led groups only 2–2.5 deer. Dominant females survived significantly longer (8.2 y) then did subordinate females (5.4 y) and fawns born to dominants were significantly more sedentary after independence. Fawn recruitment (fawns alive at 1 y) was also significantly higher for fawns born to dominant females. Members of a dominant females social group generally confined themselves to the home range of the dominant female but as they aged were seen less often with her. Dominant females occupied stable habitats free of environmental problems while subordinates occupied ranges with frequent natural and human induced disturbances. By association, fawns of dominant females inherit a stable home range that fosters improved longevity and successful fawn recruitment