Telemetry triangulation provides an estimate of a radio-tagged animal’s location that is influenced by various time and site-specific factors that can cause errors. If these errors are not considered when using location data, the conclusions drawn about animal behavior such as habitat use might be misleading. I determined home range and habitat use and selection characteristics of red-shouldered hawks (Buteo lineatus) in central Maryland. The effects of telemetry triangulation errors on these characteristics were examined. Red-shouldered hawk location estimates were obtained by triangulation to radio-tagged birds. Point estimates were determined by using ≥3 azimuths. A confidence ellipse was calculated around each point estimate which represented the error area associated with that point estimate. From the distribution of possible points within the error area of each point estimate, sampled points (simulated points) were generated for use in additional analyses to assess telemetry error. Home range sizes, based on point estimates and simulated point estimates were delineated using the convex polygon and harmonic mean models. Habitat occurrence was described from a digitized cover type map. Average home range sizes based on point estimates and simulated point estimates for 3 male hawks were larger than average home range areas for 2 female hawks. There were differences detected between pooled point estimate home range sizes and the pooled simulated point estimate home range sizes. There were fewer differences in home range sizes based on the harmonic mean model than the convex polygon. No significant seasonal differences were found for point estimate or simulated point estimate home range Sizes. Seasonal habitat use did not vary based on pooled data from all hawks on PWRC. Bottomland forest was the most frequently used habitat type; however, water habitats (ponds and river) were the most frequently selected. Bottomland forests, river swamps, terrace/bluff forests, residential/structural areas, seepage swamps, pine forests, and pine/oak forests were selected occasionally by most hawks. The two most infrequently selected habitats were powerlines and upland oak forests. / Master of Science

Thesis (M.S.)--University of Tennessee, Knoxville, 2003. / Title from title page screen (viewed Mar. 18, 2004). Thesis advisor: Lisa I. Muller. Document formatted into pages (v, 61 p. : col. ill., maps (some col.)). Vita. Includes bibliographical references (p. 55-60).

During the migration season in 2013 a study on spawning migrating salmon and the effect of water flow on the behavior was conducted of the salmon at the Forshaga hydropower station in the River Klarälven. The River Klarälven with its nine hydropower plants on the Swedish side, constituting migration obstacles for the migrating salmon. Fortum Generation AB has together with the County Administrative Board restored a salmon trap at the lowermost hydropower station in Forshaga, aiming at making it possible for the salmon to swim into the trap, and thereafter be transported by truck past the power plants and then continue their journey to the spawning grounds on their own. Unfortunately, it is believed that the trap does not work as well as it should. In this study, I focused on salmon position in relation to water flow and if the number of salmon that swam into the fish trap differed between salmon with previous experience of the trap (experienced) and salmon without experience (unexperienced). My results showed that there were significantly more inexperienced salmon that entered the trap than experienced salmon. The salmon, regardless of experience, chose a position where the flow was highest. To increase catches of salmon in the fish trap I suggest that one use more attraction water and keep the trap open more hours. My results should be of interest to managers as the trap efficiency has never been evaluated, and no earlier studies about the effect of salmon experience on trap efficiency exist. / Vandringssäsongen 2013 genomfördes en studie på lekvandrande lax och hur vattenflödet påverkade laxens beteende vid Forshaga kraftstation i Klarälven. Klarälven med dess 9 vattenkraftverk på den svenska sidan utgör vandringshinder för den lekvandrande laxen. Fortum har tillsammans med Länsstyrelsen renoverat en laxfälla i det mest nedströms liggande kraftverket i Forshaga. Syftet med fällan är att laxen ska simma in i fällan till en uppsamlingsbassäng och därefter köras med lastbil förbi kraftverken, för att därefter fortsätta vandringen på egen hand. Fiskfällans effektivitet är ifrågasatt och man vet inte hur effektiv den är. I denna studie fokuserade jag på laxens ståndplats i relation till varifrån det huvudsakliga flödet kom, samt om antalet laxar som simmar in i fiskfällan skiljde sig mellan lax med tidigare erfarenhet av fällan (erfaren) och lax utan erfarenhet av fällan (oerfaren). Mina resultat visade att det var signifikant fler oerfarna laxar än erfarna laxar som simmade in i fällan. Laxen, oavsett erfarenhet, valde ståndplats där flödet var som högst. För att öka fångsterna av lax i fiskfällan skulle mer lockvatten och fler timmar då fällan är öppen kunna bidra med mer fångst. Denna studie borde vara av intresse för inblandade aktörer i laxens förvaltning eftersom fällans effektivitet aldrig utvärderats tidigare, och dessutom har man inte studerat om tidigare erfarenhet av en fälla påverkar laxen.

M.Ing. / Please refer to full text to view abstract

Im Rahmen eines internationalen Projektes von Kranichschutz Deutschland (NABU, WWF, Lufthansa) wurden in den Jahren 1995 bis 2000 in Mecklenburg Vorpommern Untersuchungen zu Verhalten und Lebensraumansprüchen reproduzierender Graukraniche durchgeführt. Die zentrale Hypothese der Arbeit lautet: Eine gute Nahrungsverfügbarkeit, eine geringe Vegetationshöhe und ein geringer Vegetationswiderstand sollten zur Bevorzugung bestimmter Revierbereiche führen und somit die Reviergröße beeinflussen. Im Fokus standen außerdem die Wirkungen anthropogener Einflüsse. Da sich Kraniche während der Jungenaufzucht äußerst unauffällig verhalten, waren Grundlagen für effiziente Schutz- und Managementkonzepte kaum verfügbar. Erstmalig wurden die Habitatnutzung und die Reviergröße von Kranichfamilien mit Hilfe der Radiotelemetrie ermittelt (Null-Peak-Peilung). Zur Abschätzung des Vegetationswiderstandes wurde ein neues Verfahren entwickelt. Innerhalb der Reviere beeinflussten der Feldanbau mit Raps, landwirtschaftliche Störreize, die Nahrungsverfügbarkeit und die Jagdausübung die Habitatnutzungsintensität (HNI) am stärksten. Der Nahrungserwerb erfolgte in fast allen Habitattypen. Naturnahe bzw. extensiv genutzte Habitate wurden signifikant häufiger frequentiert als intensiv bewirtschaftete Nutzflächen. Die HNI der Kranichfamilien korrelierte signifikant mit der Verfügbarkeit der Nahrung. Straßen und Straßenverkehr beeinflussten die HNI ebenfalls. Der Mindestabstand zu Kreisstraßen war signifikant größer (mittlerer Abstand 308m) als zu Bundesstraßen (141m). Die Einflüsse der Vegetationshöhe und des Vegetationswiderstandes auf die HNI waren meist von geringer Bedeutung (keine Korrelation bzgl. der HNI). Habitate wurden erst gemieden, wenn bestimmte Schwellenwerte überschritten wurden (Veg.-höhe > 1m, Veg.-widerstand auf einen definierten Dummy >8N). Kranichreviere waren durchschnittlich 69,7ha (max.=131,8ha) groß.Ein Ausblick präsentiert künftige und bereits begonnene Projektvorhaben.

Chameleons are an understudied taxon facing many threats, including collection for the international pet trade and habitat loss and fragmentation. A recent field study reports a highly female-biased sex ratio in the Eastern Arc Endemic Usambara three horned chameleon, Trioceros deremensis, a large, sexually dimorphic species. This species is collected for the pet trade, and local collectors report males bring a higher price because only this sex has horns. Thus, sex ratios may vary due to differential rates of survival or harvesting. Alternatively, they may simply appear to be skewed if differences in habitat use biases detection of the sexes. Another threat facing chameleons is that of habitat loss and fragmentation. Despite enormous amounts of research, the factors of fragmentation that different species respond to is still under debate. Understanding these responses is important for current mitigation efforts as well as predicting how species will respond to future habitat alteration and climate change. My study suggests that differences in survival and detection may explain much of the observed seasonal sex skew in adult T. deremensis. Within fragmented habitat chameleons consistently responded more to edge effects and vegetative characteristics associated with fragmentation than to area or isolation effects. This may bode poorly for chameleon populations in the coming decades as climate change further alters vegetative communities and exacerbates edge effects.

No description available.

Kakapo (Strigops habroptilus) are a flightless, nocturnal parrot endemic to New Zealand. Thought to be extinct within their natural range, kakapo are currently listed as nationally critical. The current population of 86 individuals is managed by the Department of Conservation’s National Kakapo Team on two offshore islands in southern New Zealand, with all females of breeding age on Codfish Island (Whenua Hou). Kakapo only breed once every two to five years, coinciding with the mast fruiting of specific plant species. On Codfish Island, the proportion of adult female kakapo that breed in rimu (Dacrydium cupressinum) fruiting years is dependent on the quantity of fruit produced, with fewer females attempting to breed during low mast years. The purpose of this research is to investigate why only some adult female kakapo breed in low rimu fruiting years on Codfish Island, specifically assessing if foraging home range size and/or habitat selection influence breeding. A total of 506 location points were collected at night for 18 adult female kakapo between March and May 2006. These were used to estimate foraging home ranges and to assess if kakapo select for particular types of vegetation. Ecological Niche Factor Analysis was used to determine the relative importance of habitat variables in the distribution of female kakapo and to predict areas of suitable breeding habitat when rimu fruit is limited. The breeding success of individuals in 2005, a low rimu mast year, was used to identify if differences in home ranges or habitat selection occurred between breeding and non-breeding females. The large variation in foraging home range sizes recorded in this research was consistent with previous studies. Foraging home range sizes were on average twice the size for breeders than for non-breeders, suggesting that adult female kakapo may be limited in their ability to breed by the size of the area they occupy. Adult female kakapo did not randomly use vegetation on Codfish Island as some vegetation types were not used, while others were common inside foraging home ranges. Adult female kakapo utilise a broad niche and are capable of surviving in a wide range of habitats. However, breeding females were more specialised in their niche requirements than non-breeders, with breeders utilising areas with higher abundances of mature rimu trees. Females occurred in high elevation, flat areas of the island but this may have been because this is where appropriate vegetation types occurred. During low rimu mast years, breeding adult females were predicted to occupy habitat in high elevation, plateau areas with a high abundance of rimu. Areas identified as sub-optimal habitat for breeding included the coastal areas, the lower elevation area of the main valley and some ridgelines. The home ranges of all 10 breeding females contained some optimal habitat, while females who did not breed were more likely to be located in sub-optimal habitat. Although there were significant areas of optimal breeding habitat not occupied by adult female kakapo, other kakapo may have been present in these areas. To increase the proportion of females that breed in low rimu mast years, it may be necessary to remove sub-adult females or surplus adult males living in optimal breeding habitat from the island. Alternatively, females in sub-optimal breeding habitat could be fed supplementary foods or transferred to other islands where there is unoccupied suitable breeding habitat available.

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The eastern race of the Loggerhead shrike (Lanius ludovicianus ssp. migrans) is a grassland bird federally listed as endangered. There are approximately 30 pairs remaining in the Canadian wild today. Captive breeding and release programs have been developed in Canada to help alleviate the decline. However, little is known about the fate of the released birds and the factors influencing their reproductive success. To help in the understanding of the movement, behaviour and survival of the shrikes post-release, we tested whether radio telemetry was an effective technique to follow these birds. Despite limited behavioural effects in captivity, a tail-mount was not suitable for released Loggerhead shrikes due to unreliable retention times. The second portion of this study addressed the factors influencing reproductive success in captivity, including breeding behaviour and individual characteristics. Distance between individual pairs in their cages, female nesting activity and male origin were the best predictors of success. Recommendations for managers are made.