Små barn i risikosonen
نویسندگان
چکیده
منابع مشابه
Should I brood or should I hunt: a female barn owl’s dilemma
While brooding, many female raptors rely exclusively on food provisioning from males. Thus, they may forego hunting until young are about half grown before exiting the nest to undertake a first foraging trip. To investigate the mechanisms that trigger this first foraging exit, we analysed nest food provisioning, female body mass change, and nestling and female food requirements in regard to exi...
متن کاملBarn owl and sound localization
The barn owl is a nocturnal predator with excellent sound localization ability. Due to the asymmetric ears of this bird, the interaural time and level differences, respectively, provide information for the horizontal and vertical direction of a sound source. Forty years of behavioral, anatomical and physiological research on the owl’s auditory system have revealed that these two acoustic cues a...
متن کاملVernier acuity in barn owls
Vernier acuity thresholds were obtained psychophysically in three adult barn owls with vertical bars and sinusoidal gratings. A minimal displacement threshold of 0.58 arcmin was observed with the bar stimulus under binocular viewing conditions. The mean binocular bar threshold was 2.51 arcmin. Bar thresholds were lower than grating thresholds. Monocular thresholds, obtained in one bird only, we...
متن کاملOtoacoustic Interrelationships of the Barn Owl
Significant debate still exists about the biophysical mechanisms at work in otoacoustic emission (OAE) generation and how such may differ between mammals and non-mammals given gross morphological differences (e.g., existence of basilar membrane traveling waves, degree of tectorial membrane coupling). To further elucidate general principles at work, we examined the barn owl for interrelationship...
متن کاملGloger’s rule in North American Barn Owls
Studying the geographic variation of phenotypic traits can provide key information about the potential adaptive function of alternative phenotypes. Gloger’s rule posits that animals should be darkvs. light-colored in warm and humid vs. cold and dry habitats, respectively. The rule is based on the assumption that melanin pigments and/or dark coloration confer selective advantages in warm and hum...
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ژورنال
عنوان ژورنال: Tidsskrift for Den norske legeforening
سال: 2014
ISSN: 0029-2001
DOI: 10.4045/tidsskr.14.0534