Bird remains from the Middle Paleolithic levels (MIS3) of Llonin Cave (Peñamellera Alta, Asturias, Spain)

Birds are abundant in fossil assemblages of Quaternary sites; they can be used in landscape recon­struction as they are well adapted to the environment. Here we present the analysis of the avian assemblage from the Middle Paleolithic levels of the Llonin Cave, where 558 bird remains have been recovered from levels G-VI and CP-VIII, belonging to at least ten different taxa: Aves indet., Galliformes indet., Lagopus lagopus Linnaeus, 1758, Tetrastes bonasia Linnaeus, 1758, Columba livia/oenas Gmelin, 1789/Linnaeus, 1758, Passeriformes indet., Alaudidae indet., Motacilla sp., Turdus sp., Corvidae indet., Garrulus glandarius Linnaeus, 1758, Pyrrhocorax sp., Pyrrhocorax pyrrhocorax Linnaeus, 1758, Pyrrhocorax graculus Linnaeus, 1766 and Corvus corax Linnaeus, 1758. This assemblage is similar to other assemblages from the Upper Pleistocene of the north of the Iberian Peninsula, and it reflects a mixed landscape, with open areas and woodland. The taphonomic analysis points to a mixed origin of the accumulation, mainly formed by medium-sized corvids dying in the cave, and also raptors accumulating their prey.

Survival and cause-specific mortality of harvested willow ptarmigan (Lagopus lagopus) in central Norway

Survival is a key demographic component that often vary as a result of human activities such as recreational harvest. Detailed understanding of seasonal variation in mortality patterns and the role of various risk factors is thus crucial for understanding the link between environmental variation and wildlife population dynamics, and to design sustainable harvest management systems. Here, we report from a detailed seasonal and cause-specific decomposition of mortality risks in willow ptarmigan (Lagopus lagopus) in central Norway. The analyses are based on radio collared (n=188) birds that were monitored across all seasons, and we used time-to-event models for competing risks to estimate mortality patterns. Overall, annual survival was estimated at 0.43 (SE: 0.04), with no distinct difference among years (2015/16 to 2018/19) or between sexes. Analysis of mortality risk factors revealed that on the annual basis, the risk of harvest mortality was lower than the risk of dying from natural causes. However, during the autumn harvest season (Sept. – Nov.), survival was low and the dominating cause of mortality was harvest. During winter (Dec. – Mar.) and spring seasons (Apr. - May), survival was in general high and did not vary between males and females. However, during the spring season juveniles (i.e. birds born last year) of both sexes had lower survival than adults, potentially because they are more prone to predation. During the summer season (June – Aug.) females experienced a higher hazard than males, underlining the greater parental investment of females during egg production, incubation and chick rearing compared to males. Our analyses provide unique insight into demographic and seasonal patterns in willow ptarmigan mortality risks in a harvested population, and revealed a complex interplay across seasons, risk factors and demographic classes. Such insight is valuable when designing sustainable management plans in a world undergoing massive environmental perturbations.