New perspectives on Neanderthal dispersal and turnover from Stajnia Cave (Poland)

The Micoquian is the broadest and longest enduring cultural facies of the Late Middle Palaeolithic that spread across the periglacial and boreal environments of Europe between Eastern France, Poland, and Northern Caucasus. Here, we present new data from the archaeological record of Stajnia Cave (Poland) and the paleogenetic analysis of a Neanderthal molar S5000, found in a Micoquian context. Our results demonstrate that the mtDNA genome of Stajnia S5000 dates to MIS 5a making the tooth the oldest Neanderthal specimen from Central-Eastern Europe. Furthermore, S5000 mtDNA has the fewest number of differences to mtDNA of Mezmaiskaya 1 Neanderthal from Northern Caucasus, and is more distant from almost contemporaneous Neanderthals of Scladina and Hohlenstein-Stadel. This observation and the technological affinity between Poland and the Northern Caucasus could be the result of increased mobility of Neanderthals that changed their subsistence strategy for coping with the new low biomass environments and the increased foraging radius of gregarious animals. The Prut and Dniester rivers were probably used as the main corridors of dispersal. The persistence of the Micoquian techno-complex in South-Eastern Europe infers that this axis of mobility was also used at the beginning of MIS 3 when a Neanderthal population turnover occurred in the Northern Caucasus.

Diet of the Nestling Tree Swallow

Dietary samples from nestling Tree Swallows (Tachycineta bicolor) in northwestern Minnesota were compared to invertebrate availability as measured by aerial tow nets. The majority of the biomass in the nestlings' diet was adult insects with larval stages of aquatic origin, while absolute numbers of insects of both aquatic and terrestrial origin were similar. Orders of invertebrates in the diet and available were similar in number but not in biomass. Diet showed little variation by time of day, date of sampling or the age of the nestling. The mean number of odonates in the nestling Tree Swallows' diet increased exponentially as the percentage of open water and open water + cattail marsh increased within a 400-m foraging radius. Dieta de los Pichones de Tachycineta bicolor Resumen. Se compararon muestras dietarias de pichones de la golondrina Tachycineta bicolor tomadas en el noroeste de Minnesota con la disponibilidad de invertebrados medida con redes aéreas. La mayor parte de la biomasa en la dieta de los pichones correspondió a insectos adultos con estadíos larvales de origen acuá tico, mientras que los números absolutos de insectos de origen acuático y no acuático fueron similares. Los órdenes de invertebrados presentes en la dieta y disponibles en el ambiente fueron similares en números pero no en biomasa. La dieta mostró poca variación entre horas del día, fechas de muestreo o edad de los pichones. El número promedio de odonatos en la dieta de los pichones de T. bicolor aumentó exponencialmente a medida que se incrementó el porcentaje de agua abierta y de agua abierta + pantanos de espadañas dentro de un radio de forrajeo de 400 m.

Foraging movements of female bushy-tailed wood rats (Neotoma cinerea)

Nocturnal foraging movements of female bushy-tailed wood rats (Neotoma cinerea) in the Canadian Rocky Mountains, Alberta, were monitored using radiotelemetry over two breeding seasons (1993–1994). Total distance moved and maximum foraging radius from the nest per night were calculated for individual females throughout the breeding season. Movements during pregnancy, lactation, and the postreproductive period did not differ significantly. Females moved much farther (up to 470 m) from the nest than previously reported for this species (60 m). Such long-distance movements may be related to the availability of an appropriate food supply.

Aggressiveness and the Foraging Behaviour of Young-of-the-Year Brook Charr (Salvelinus fontinalis)

Individual young-of-the-year brook charr (Salvelinus fontinalis) were observed in the field to relate their aggressiveness to their body size, the size and quality of their foraging site, and their feeding rate. Aggressive charr were 13% larger than nonaggressive conspecifics observed on the same day in the same area. Aggressive fish had a lateral foraging radius 29% larger than nonaggressive fish and a 45% greater mean distance to neighbours, even when the effect of body size was removed by analysis of covariance. Aggressive fish of two size categories (20–29 and 40–99 mm) made 70 and 55% more feeding attempts per unit time, respectively, than nonaggressive fish of the same size. Number of prey items in stomachs was significantly and positively correlated with feeding attempt rate. In addition, aggressive fish appeared to occupy more preferred sites, since their sites were significantly more likely to be reoccupied after their removal than were sites occupied by nonaggressive fish. These results are consistent with the hypothesis that defence of a foraging site is a better tactic than ignoring conspecifics.