Barred Woodcreeper (Dendrocolaptes certhia) Science Article 1 abstract The observations reported here were made while I attended the Tropical Entomology Course offered by the Organization for Tropical Studies in Costa Rica sponsored by the National Science Foundation. In spite of the brevity of the study, I believe that the results are a useful addition to […]
Photos of Micrastur species in Peru, covering the Surinam species
Barred Forest Falcon (Micrastur ruficollis) Science Article 4 abstract Five of the seven species of the mysterious Forest-falcons (Micrastur: Falconidae) occur en Los Amigos river basin, Madre de Dios, Peru Ursula Valdez, Boletin SAO Vol. XVI (No. 02) – Dic. 2006 Download article download full text (pdf)
NEST-SITE CHARACTERISTICS AND BREEDING DENSITY OFTWO SYMPATRIC FOREST-FALCONS IN GUATEMALA
Barred Forest Falcon (Micrastur ruficollis) Science Article 3 abstract The Barred Forest-Falcon (Micrastur ruficollis) and Collared Forest-Falcon (M. semitorquatus) are cavity nesters with similar geographic distributions but differences in body size. For Barred and Collared forest-falcons, nest height averaged 17 and 20 m above ground, nest tree dbh averaged 95 and 167 cm, and nest […]
First record of a Barred Forest-falcon (Micrastur ruficollis) nesting in a cliff pothole
Barred Forest Falcon (Micrastur ruficollis) Science Article 1 abstract Between 5 March-13 May 1996 we observed a pair of Barred Forest-falcons in Peten, Guatemala demonstrating nuptial behavior and utilizing a cliff pothole as a nest site. Each morning and evening of 5-10 March, 8-13 April, and 8-13 May 1996, we heard a male Barred Forest-falcon […]
Estimation of annual adult survival rates of Barnacle Geese Branta leucopsis using multiple resightings of marked individuals.
Barnacle Goose (Branta leucopsis) Science Article 5 abstract Accuracy and feasibility of three different methods to estimate adult annual survival rates in a migratory population of Barnacle Geese Branta leucopsis are examined. Estimates from resightings of birds marked with coloured leg-rings prve to be the more accurate. Bothe estimates derived from recoveries of metal-ringed birds, […]
The flight energetics of barnacle geese (Branta leucopsis) underwild and captive conditions
Barnacle Goose (Branta leucopsis) Science Article 2 abstract Experimental data on the relationship between mean heart rate (fH) and mean rate of oxygen consumption (VO2) ofcaptive barnacle geese during flights in a wind tunnel are reviewed in terms of their capacity to predict the mean VO2 of wildbarnacle geese, based on recordings of their fH […]
Foraging behavior and site selection of Barnacle Geese Branta leucopsis in a traditional and newly colonized spring staging habitat
Barnacle Goose (Branta leucopsis) Science Article 3 abstract For three weeks in May the Svalbard Barnacle Geese Branta leucopsis stop to feed on the archipelagos of the Helgeland district, up to 50 km out to sea off western Norway. However, since 1980 an increasing part of the population has moved to a newly exploited agricultural […]
Travels and traditions: long-distance dispersal in the Barnacle Goose Branta leucopsis based on individual case histories
Barnacle Goose (Branta leucopsis) Science Article 12 abstract Long-distance dispersal can have far-reaching consequences for the amount of gene flow between populations. However, individuals usually disperse to places well outside the study area, which makes long-distance dispersal hard to study. In this study, the fate of c. 4500 individually marked Barnacle Geese Branta leucopsis hatched […]
Variation in growth of young and adult size in Barnacle Geese Branta leucopsis: Evidence for density dependence
Barnacle Goose (Branta leucopsis) Science Article 7 abstract A colony of Svalbard Barnacle Geese Branta leucopsis was studied near Ny Alesund, Spitsbergen. Breeding started in 1980 and the colony size followed a sigmoidal curve with little increase in numbers in the period 1992-1995. Over the period 1991-1995 gosling growth declined, mortality during growth increased and […]
Site tenacity and mobility of staging Barnacle Geese
Barnacle Goose (Branta leucopsis) Science Article 6 abstract The within season site tenacity of staging Barnacle Geese Branta leucopsis was investigated using two years of observations of individually colour ringed birds in Schleswig Holstein/Germany. Arrays of observations of individual geese show that some birds move among areas in Schleswig Holstein within seasons. Movements occur over […]