The University of Manitoba Field Station Delta Marsh 1982 Annual Report Number 17

The University Field .Station continues to be an active focus for research and teaching. It serves the needs of field courses, workshops, seminars and short courses and increasing use by researchers. These varied contributions make the Field Station a vital unit in the University's academic program. 1982 was certainly a successful season . Staff Dr. Jennifer M. Shay Dr . Robert M.R. Barclay Support Staff Mr. Ken May Mrs. Diane May Mr . George Cosens Ms. Adele Vust Ms . Lucia Flynn Ms. Joyce Kendrick Faculty Dr . Tom Booth Dr . J .Bruce Falls Dr . Jack Gee Dr. Gordon G. C. Robinson Dr. Spencer G. Sealy Graduate Students Gloria Biermann Gordon Goldsborough Dan Guinan Heidi den Haan Andrew Horn Tawfik Muhsin lain Suthers June Tugwood P. L. Wlong Project Assistants Barbara Beaver Friederike Schneider Melissa Todd Christina Zarowsky 1982 PERSONNEL Director Resident Biologist Caretaker Cook/Housekeeper Summer Assistant Summer Assistant Administrative Clerk (January to August) Administrative Clerk (from August) Department of Botany Department of Zoology , University of Toronto Department of Zoology Department of Botany Department of Zoology Department of Zoology Department of Botany Department of Zoology Department of Zoology Department of Zoology, University of Toronto Department of Botany Department of Zoology Department of Zoology Department of Biology, Lakehead University Department of Zoology Department of Botany, NSERC Summer Scholar Department of Zoology Department of Zoology , University of Toronto Research Don Thompson completed hi s MSc. thesis and has begun a Ph.D. program in the Department of Pla nt Science . Fifteen research projects were undertaken , five by faculty members, four by Ph.D. candidates, five by ~1 Sc. candidates and one by an NSERC Summer Scholar . Project titles and inve stiga t ors are given below : Barclay , R.t·1. R. Ph.D. Pohajdak, G. C. den Haan , H. Falls, J .B. Ph.D. Goldsborough , G. Guinan , D. Horn, A. Muhsin, T. Schneider, F. Sealy , S. G. Ph.D. Shay, J .M. Ph . D. Suthers , I . ~1. Tugwood, J . Wong, P.L. Foraging behavior of the insectivorous bats at Delta Marsh Dynamics of foraging and food resource use in a community of nesting birds (Ph . D. candidate) Patterns of fall migration and molt in wood warblers (MSccandidate) . Song matching in western meadowlarks . An investigation of t he influence of herbicides upon algal communities. (MSc candidate) Foraging strategy of house wrens . (MSc candi date) Graded signals in the song repertoires of western meadowlarks . (P h.D . candidate) Mycological studies of select ed salt marsh succulents . (Ph.D. candidate ) An investigation of colonization of submerged surfaces by diatoms. (NSERC Summer Scholar) Population structure in birds in the dune ridge community . Dynamics of breeding in a passerine bird communi ty . A Phragmites australis. dominated community three years after spring , summer and fall burning . Distribution and reactions to hypoxia of some marsh -dwelling fish. (MSc candidate) Habitat variables affecting host - nest selection by the brown-headed cowbird. (MSc candidate) Studies of the acuarioid nematod es of waders and rails. (MSc candidate) The Annual Seminar was held on January 23rd 1982 with progress reports given by faculty and graduate students . Dr . Bruce Batt , from the Delta Waterfowl Research Station , gave a paper on their Marsh Ecology Re search Program

Roost site selection and roosting ecology of forest dwelling bats in southern British Columbia

We used radiotelemetry to examine the roost-site preferences of four species of tree-roosting bats (Eptesicus fuscus, Lasionycteris noctivagans, Myotis evotis, and M. volans) in southern British Columbia, Canada, by radio-tracking bats to their day roosts. We found a total of 21 roost trees: 14 roosts were beneath loose bark, 5 were in cavities excavated by woodpeckers, and 2 were in natural cavities. Entrance height increased with tree height, but roost entrances tended to be situated below the level of the canopy. Of the 22 tree and site variables examined, only 3 significantly discriminated between roost trees and available trees: tree height, distance to the nearest available tree, and percent canopy closure. Bats preferred tall trees associated with low percent canopy closure and a short distance to the nearest available tree. Bats roosted in western white pine, and to a lesser extent ponderosa pine and western larch, in intermediate stages of decay more often than would be expected at random. Bats switched roosts frequently. The distance between Subsequent roost trees was short, suggesting a degree of fidelity to a particular group of trees or area of forest. The number of days of rain during the roosting period significantly influenced the number of days spent in a particular roost, and thus ambient conditions may restrict the frequency with which bats can switch roosts

Habitat Selection by Bats in Fragmented and Unfragmented Aspen Mixedwood Stands of Different Ages

To determine if bats prefer certain ages of aspen mixedwood forest for roosting and foraging, and to predict the impacts of logging on bats, we compared the relative abundances and foraging activities of bats in young, mature, and old stands in and , using bat detectors. In , we also assessed post-logging bat abundances in two of the mature and two of the old stands. We tracked radio-tagged Myotis lucifugus and Lasionyc- teris noctivagans to roost trees, which we measured and compared to a random sample of wildlife trees. Mean total activity of all bats was signifi- cantly greater in old than in young or mature stands. It also appeared greater in unfragmented than fragmented stands, but not significantly so. All roost trees were in old forests. Bats preferred tall (mean: . m), newly dead Populus spp. with heart rot and low leaf cover (mean: %). Tree-roosting colonies were small (– bats) and transient. Bats likely select trees large enough to house colonies and provide suitable tempera- tures, and these trees are only available in old stands. Roost preference likely explains observed activity patterns. To sustain bat populations in these forests, old stands must be retained and roost sites preserved by managing the forest at the stand level

Temperature-dependent consumption of spiders by little brown bats (<i>Myotis lucifugus</i>), but not northern long-eared bats (<i>Myotis septentrionalis</i>), in northern Canada

Intraspecific variation in diet has been observed in many species, including the geographically widespread little brown bat (Myotis lucifugus (Le Conte, 1831)). Spider consumption by M. lucifugus is more common in northern regions of their distribution, possibly due to reduced availability of aerial prey during low temperatures. However, in previously studied northern regions, M. lucifugus was the only bat species captured. The purpose of our study was to examine whether there is overlap in the diet and morphology of M. lucifugus and the northern long-eared bat (Myotis septentrionalis (Trouessart, 1897)), a species that commonly gleans prey, in the Northwest Territories, Canada. There were significant differences in the dietary composition and wing morphology of the two species, suggesting partitioning of resources. Both species consumed spiders, although unlike M. septentrionalis, the probability of M. lucifugus consuming spiders was significantly greater at low temperatures. Myotis lucifugus demonstrated a different pattern of spider consumption than in other northern regions where it consumes spiders throughout the summer, suggesting the possibility of resource competition where M. lucifugus overlaps with M. septentrionalis. Further research is needed to determine whether arthropods are seasonally limiting at high latitudes and to examine how these species capture nonaerial prey, including spiders.</jats:p

A non-commensal maternity roost of the little brown bat (Myotis lucifugus)

There is no abstrac

Influence of urbanization on demography of little brown bats (Myotis lucifugus) in the prairies of North America

10.1371/journal.pone.0020483PLoS ONE65e2048

Differences in the foraging behaviour of male and female Egyptian fruit bats (<i>Rousettus aegyptiacus</i>)

Male and female animals frequently have different foraging behaviours owing to differences in body size or nutritional demand, or to intraspecific competition. We studied foraging by Egyptian fruit bats ( Rousettus aegyptiacus (E. Geoffroy, 1810)) in Cape Town, South Africa, to test predictions based on differences in nutritional demand during reproduction. Using radiotelemetry, we compared emergence, return, and foraging times of males and females during pregnancy and lactation. We also determined home-range size, habitat use, and use of figs (genus Ficus L.), which are a potential source of calcium for lactating females. During the pregnancy period, males left their roost later than females and were away from the roost for shorter periods. There were no differences in timing of foraging during lactation. Females foraged in native forest more than males did, but home-range size did not differ. There was no evidence that females fed on figs more than males did. Differences in foraging behaviour were not as predicted based on nutritional and energetic differences. The small population may have meant that there was little competition for food, and figs may have provided a profitable source of energy for both males and females. Differences in the timing of foraging are best explained by the need for males to defend roosting sites. </jats:p

Consumption of spiders by the little brown bat (<i>Myotis lucifugus</i>) and the long-eared myotis (<i>Myotis evotis</i>) in the Rocky Mountains of Alberta, Canada

Intraspecific variation in diet and (or) foraging behaviour is one way in which species are able to occupy wide geographical areas with variable environments. The little brown bat (Myotis lucifugus (Le Conte, 1831)), a primarily aerial insectivorous bat, consumes spiders in low temperatures at the start and end of summer in Northwest Territories, Canada, but it consumes spiders all summer, even during high aerial insect abundance, in Alaska, USA. There are no competitors of M. lucifugus in Alaska, but there are in Northwest Territories, suggesting that aerial insect abundance and competition from gleaning bats influences when M. lucifugus consumes spiders. In the Kananaskis area of the Rocky Mountains of Alberta, Canada, we investigated spider consumption by M. lucifugus and the long-eared myotis (Myotis evotis (H. Allen, 1864)), a species more adept at gleaning, to better understand when bats consume spiders. Fecal sample analysis indicated that M. evotis consumed spiders all season long, with greater consumption when the bats were caught near water. Myotis lucifugus did not consume spiders at all. This suggests that M. lucifugus opportunistically consumes spiders when encountered, but does not encounter them in Kananaskis where it forages primarily over open water, unlike in Northwest Territories where it forages in the interior of forests and may encounter spiders more frequently.</jats:p

Effects of environmental variables on the calling behaviour of Northern Leopard Frogs (<i>Lithobates</i> <i>pipiens</i>) in Alberta, Canada

Breeding behaviour of Temperate Zone amphibians is influenced by environmental variables, but the initiation of calling (phenology) and influences on calling activity may vary with species and region. We investigated the influence of the timing of ice melt, water temperature, and photoperiod on the breeding phenology of the Northern Leopard Frog (Lithobates pipiens (Schreber, 1782)) in southern Alberta, Canada, using automated recording units. We also examined the influence of wind speed, relative humidity, water temperature, and time of day on calling activity. The initiation of calling varied by 13 days at our three sites, suggesting that calling was influenced more by water temperature and timing of ice melt than photoperiod. Calling was first observed 8–11 days after ice melt at water temperatures of 7.5–8 °C at our sites. No calling was detected at water temperature &lt;5 °C. We recorded nocturnal and diurnal calling at all sites; &gt;50% of calling was diurnal, even on days with warm overnight temperatures. Calling activity was influenced by time of day, water temperature, wind, and relative humidity. Our results suggest that date of initiation of calling varies considerably among breeding ponds and that the time of day of peak calling varies with both site and water temperature. </jats:p