Annual movement and migration of adult pikeperch in a lowland river

The downstream migration of 46–66 cm radio-tagged adult pikeperch Stizostedion lucioperca , in the River Gudenaa, Denmark, from late September to late December, coincided with a reduction in the frequent occurrence of prey fish in the tagging area, and hence was interpreted as a feeding migration. The upstream migration from March to mid-April in spring took place prior to spawning which occurred from late April to June.     

Long-Distance Dispersal of a Rescued Wolf From the Northern Apennines to the Western Alps

ABSTRACT By using Global Positioning System technology, we documented the long-distance dispersal of a wolf (Canis lupus) from the northern Apennines in Italy to the western Alps in France. This is the first report of long-distance dispersal of wolves in the human-dominated landscapes of southern Europe, providing conclusive evidence that the expanding wolf population in the Alps originates from the Apennine source population through natural recolonization. By crossing 4 major 4-lane highways, agricultural areas, and several regional and provincial jurisdictions, the dispersal trajectory of wolf M15 revealed a single, narrow linkage connecting the Apennine and the Alpine wolf populations. This connectivity should be ensured to allow a moderate gene flow between the 2 populations and counteract potential bottleneck effects and reduced genetic variability of the Alpine wolf population. The case we report provides an example of how hard data can be effective in mitigating public controversies originating from the natural expansion and recolonization processes of large carnivore populations. In addition, by highlighting the connectivity between these 2 transboundary wolf populations, we suggest that documenting long-distance dispersal is particularly critical to support population-based, transboundary management programs.     

Roosting behaviour is related to reproductive strategy in brood parasitic cowbirds

Shiny Cowbirds Molothrus bonariensis and Screaming Cowbirds Molothrus rufoaxillaris are closely related brood parasites but the former is socially polygynous or promiscuous and an extreme host generalist, whereas the latter is socially monogamous and parasitizes almost exclusively one host. Females of both species lay in relative darkness, before dawn, relying for host nest location on previous days’ prospecting activity, or possibly on following better‐informed roost associates. We studied the temporal and spatial patterns of roosting behaviour in these species to test the hypothesis that roosting behaviour of cowbirds is related to their breeding strategy (brood parasitism) and reflects differences in strategies between species. We recorded fidelity to a roost, location fidelity within a roost, inter‐individual spatial associations and timing of roost departures and parasitic events, using tagged individuals. Female Shiny Cowbirds and both sexes of Screaming Cowbirds showed marked fidelity in roosting location, and roost departures occurred both during and after the known time window for parasitism, with earlier departures probably corresponding to laying days. Screaming Cowbird females and males that were trapped together and showed high levels of association during the day, also showed high levels of association in the roost. We describe the spatial and temporal patterns of a relatively poorly known aspect of avian ecology in general and the behaviour of brood parasites in particular.     

Radiotagged fledgling Savannah Sparrows Passerculus sandwichensis at risk of entanglement in vegetation

Radiotelemetry is an essential method for studying the movements and survival of cryptic grassland bird fledglings. There is mixed evidence on the effects of wearing radio‐transmitters for passerines, with negative consequences probably under‐reported. In one season of a 2‐year study, we found 23% of radio‐transmitters and/or antennas deployed on fledgling Savannah Sparrows Passerculus sandwichensis had become entangled in vegetation, consequently harming the fledglings in two of seven cases. It is important for researchers to share their information on any negative consequences of attaching radio‐transmitters to songbirds in order to improve methods and to harm fewer individuals in future studies.     

Migration and wintering strategies in vulnerable Mediterranean Osprey populations

A broad range of migration strategies exist in avian species, and different strategies can occur in different populations of the same species. For the breeding Osprey Pandion haliaetus populations of the Mediterranean, sporadic observations of ringed birds collected in the past suggested variations in migratory and wintering behaviour. We used GPS tracking data from 41 individuals from Corsica, the Balearic Islands and continental Italy to perform the first detailed analysis of the migratory and wintering strategies of these Osprey populations. Ospreys showed heterogeneous migratory behaviour, with 73% of the individuals migrating and the remaining 27% staying all year round at breeding sites. For migratory individuals, an extremely short duration of migration (5.2 ± 2.6 days) was recorded. Mediterranean Ospreys were able to perform long non‐stop flights over the open sea, sometimes overnight. They also performed pre‐ and post‐migratory trips to secondary sites, before or after crossing the sea during both autumn and spring migration. Ospreys spent the winter at temperate latitudes and showed high plasticity in habitat selection, using marine bays, coastal lagoons/marshland and inland freshwater sites along the coasts of different countries of the Mediterranean basin. Movements and home‐range areas were restricted during the wintering season. The short duration of trips and high levels of variability in migratory routes and wintering grounds revealed high behavioural plasticity among individuals, probably promoted by the relatively low seasonal variability in ecological conditions throughout the year in the Mediterranean region, and weak competition for non‐breeding sites. We stress the importance of considering the diversity in migration strategies and the particular ecology of these vulnerable populations, especially in relation to proactive management measures for the species at the scale of the Mediterranean region.     

Movement patterns and herd dynamics among South African giraffes (Giraffa camelopardalis giraffa)

Giraffes reside in a fission–fusion social system, with sex, age proximity, kinship and home range overlap accounting for some of the variance in herd composition, while season, sex, age and time of day influence diet, home range size and distance travelled. To increase our knowledge of habitat use and fission–fusion herd dynamics, we placed GPS devices on eight adult female South African giraffes (Giraffa camelopardalis giraffa) living in the Khamab Kalahari Nature Reserve (South Africa). We tested four predictions about how season, kinship, home range and travel patterns influence habitat use and herd dynamics. Our two key findings were that females with a greater degree of home range overlap were more likely to form herds, but the degree of overlap was independent of the amount of time that they spent together in a herd, and that on the day prior to herd formation, females travelled about twice as far as their daily average and tended to move directly towards their future herd mate. We conclude that habitat use and movement patterns regulating fission–fusion dynamics reflect an interaction of ecological, social and reproductive factors operating in tandem, not independently.     

Activity rhythm and action range of workers of the invasive hornet predator of honeybees Vespa velutina,measured by radio frequency identification tags

In social insects, the activity rhythm of foragers and their action range determinate the activity of the colony. In vespids, which are mostly predators, the foraging range of workers determines their maximum predation pressure round the nest. One of these species, Vespa velutina, a recently invasive species introduced into Europe, exerts a strong predation on honeybees at the hive. Therefore, the definition of its activity rhythm and spatial range of predation is of primary importance. Using radio frequency identification tags (RFID), two experiments were carried out to (a) determine their return ability (called homing) in releasing 318 individuals at different distance from their colony and (b) monitor their foraging activity rhythm and the duration of their flights based on 71 individuals followed 24 hr/24 during 2 months. The homing ability of V. velutina was evaluated to be up to 5,000 m and was not affected by the cardinal orientation of release point. The lag time to return to the nest increased with the distance of release. Most of the flight activity took place between 07:00 a.m. and 08:00 p.m., hornets doing principally short flights of less than an hour. Foraging range was thus estimated ca. 1,000 m around the nest. This study of V. velutina assisted by RFID tags provides for the first time a baseline for its potential foraging distance that increase our knowledge of this species to (a) refine more accurately models for risk assessment and (b) define security perimeter for early detection of predation on invasion front.     

Homing movements of displaced stream-dwelling brown trout

In April and May of 1993, 12 of 14 brown trout (202–288 mm), tagged with radio transmitters and displaced over 800–3600 m in a natural river system, returned to the areas from which they were captured. Homing was generally directed and rapid (up to 1·22 body lengths s⁻¹ against the flow). Homing commenced within 65 min of displacement for four of five trout displaced downstream, and within 4 days for those displaced above the confluence of a home tributary burn with the main stem of the river.     

The COP9 complex: a link between photomorphogenesis and general developmental regulation?

Light signals perceived by photoreceptors are transduced into the nucleus to regulate gene expression and development. The COP9 protein complex localized in the nucleus has a central role in modulating light-regulated development, and may have a role in regulating development in general in all organisms. This review considers recent advances in the study of the COP9 complex and its sub-units in plant and animal systems, and discusses the possible functional implications.