Dune Hares: Population Indices, Home Range Size, and Habitat Selection of the European Hare on a Danish Island.

Population indices, such as transect counts of animals, can provide important information concerning population changes over time. Moreover, data concerning the home range size and habitat selection of individuals can provide valuable insight into spatial requirements of animals and how they can adapt to variable environments. Here, we describe the population development of European hares () and investigated home range sizes and habitat selection of six radio-tagged individuals on the small (80 ha) Danish Wadden Sea island Langli.

Monitoring Colonies of Large Gulls Using UAVs: From Individuals to Breeding Pairs.

Measuring success or failure in the conservation of seabirds depends on reliable long-term monitoring. Traditionally, this monitoring has been based on line transects and total or point counts, all of which are sensitive to subjective interpretation. Such methods have proven to consistently record fewer individuals than intensive efforts, while requiring many hours of fieldwork and resulting in high disturbance.

Unmanned Aircraft Systems as a Powerful Tool to Detect Fine-Scale Spatial Positioning and Interactions between Waterbirds at High-Tide Roosts.

The surveillance of behavioral interactions between individuals in bird populations is important to understand social dynamics and explain distribution patterns caused by competition for food and space. For waterbirds, little is known about interactions between individuals at high-tide roosts. In the present study, we used surveying with unmanned aircraft systems (UASs) to provide enhanced information on previously hidden aspects of the highly dynamic communities of roosting waterbirds in the non-breeding season.

A Test of Positive Association for Detecting Heterogeneity in Capture for Capture-Recapture Data.

Unlabelled: The Cormack-Jolly-Seber (CJS) model assumes that all marked animals have equal recapture probabilities at each sampling occasion, but heterogeneity in capture often occurs and should be taken into account to avoid biases in parameter estimates. Although diagnostic tests are generally used to detect trap-dependence or transience and assess the overall fit of the model, heterogeneity in capture is not routinely tested for. In order to detect and identify this phenomenon in a CJS framework, we propose a test of positive association between previous and future encounters using Goodman-Kruskal's gamma.

What does three years of hunting great cormorants, Phalacrocorax carbo, tell us? Shooting autumn-staging birds as a means of reducing numbers locally.

Background: The population of great cormorants, Phalacrocorax carbo, has increased markedly in Europe in the last 30 years, creating conflicts primarily with fisheries' interests. Some advocate that there should be a reduction in bird numbers on anything from local to regional and pan-European levels. The effect of attempts to reduce cormorant numbers by shooting to kill and by shooting to reinforce the scaring of birds in two Danish fjords was studied.

Fitness consequences of timing of migration and breeding in cormorants.

In most bird species timing of breeding affects reproductive success whereby early breeding is favoured. In migratory species migration time, especially arrival at the breeding grounds, and breeding time are expected to be correlated. Consequently, migration time should also have fitness consequences.

Generation time and temporal scaling of bird population dynamics.

Theoretical studies have shown that variation in density regulation strongly influences population dynamics, yet our understanding of factors influencing the strength of density dependence in natural populations still is limited. Consequently, few general hypotheses have been advanced to explain the large differences between species in the magnitude of population fluctuations. One reason for this is that the detection of density regulation in population time series is complicated by time lags induced by the life history of species that make it difficult to separate the relative contributions of intrinsic and extrinsic factors to the population dynamics.

Evidence for density-dependent survival in adult cormorants from a combined analysis of recoveries and resightings.

1. The increasing population of cormorants (Phalacrocorax carbo sinensis) in Europe since 1970 has led to conflicts with fishery interests. Control of cormorant populations is a management issue in many countries and a predictive population model is needed.

Diagnosing a decline in return rate of 1-year-old cormorants: mortality, emigration or delayed return?

1. In long-lived birds with delayed recruitment, variation in prebreeding population parameters is difficult to study, although potentially important. Cormorants (Phalacrocorax carbo sinensis) often return to their natal colony when 1 year old, enabling direct study of first-year survival and emigration.