ABSTRACT
Bird migration is typically associated with a latitudinal movement from north to south and vice versa. However, many bird species migrate seasonally with an upslope or downslope movement in a process termed altitudinal migration. Globally, 830 of the 6,579 Passeriformes species are considered altitudinal migrants and this pattern has emerged multiple times across 77 families of this order. Recent work has indicated an association between altitudinal migration and diet, but none have looked at diet as a potential evolutionary driver. Here, we investigated potential evolutionary drivers of altitudinal migration in passerines around the world by using phylogenetic comparative methods. We tested for evolutionary associations between altitudinal migration and foraging guild and primary habitat preference in passerines species worldwide. Our results indicate that foraging guild is evolutionarily associated with altitudinal migration, but this relationship varies across zoogeographical regions. In the Nearctic, herbivorous and omnivorous species are associated with altitudinal migration, while only omnivorous species are associated with altitudinal migration in the Palearctic. Habitat was not strongly linked to the evolution of altitudinal migration. While our results point to diet as a potentially important driver of altitudinal migration, the evolution of this behavior is complex and certainly driven by multiple factors. Altitudinal migration varies in its use (for breeding or molting), within a species, population, and even at the individual level. As such, the evolution of altitudinal migration is likely driven by an ensemble of factors, but this study provides a beginning framework for understanding the evolution of this complex behavior.
ABSTRACT
To investigate the science of animal welfare for zoo and wild animals in the period from 1966 to 2007, we conducted a bibliometric analysis of abstracts downloaded from The Web of Science((c)) database using the keyword combination "Animal welfare, Zoo* and wild" in the topic field. In total we downloaded 1,125 abstracts, which were classified into the following categories: year of publication; environment of the study (e.g., zoo) or theoretical; area of knowledge (e.g., conservation in situ); number of experimental animals used; species; addresses of authors; taxonomic classification; publication language; journal name; number of citations received. Since 1990, there has been a rapid increase in the number of articles published in this area of animal welfare. One worrying result was that published articles were predominately of a theoretical nature (58.65%, N=563). Most of the articles were published by authors either in Europe (47.43%, N=480) or North America (37.65%, N=381) and written in English (87.71%, N=971). The majority of experimental studies were conducted with mammals (75.92%, N=391), and had small sample sizes (N=7 for zoo-based studies). In terms of impact factor (IF), the journals in this study had a median factor equivalent to that for the area of biological sciences (median IF=1.013). Little knowledge cross-over from farm animal welfare was found (only four articles) in this study. In conclusion, zoo and wild animal welfare as a science may benefit from a greater interaction with farm animal welfare.
