摘要:

The study examines some aspects of gross morphology in Falconiformes and Strigiformes. It is hypothesized that, in predatory birds, hunting strategy might influence the relative size of skeletal musculature and length of the digestive tract. Falconiform species were categorized as either ‘attackers’ or ‘searchers’ depending on the degree to which active, powered pursuit is required for prey capture. Attacking species feed predominantly on avian prey, requiring extreme agility, speed and acceleration for prey capture. Searchers feed largely on relatively slow‐moving mammals and carrion. Comparisons between species of attackers and searchers showed that the former had heavier pectoral muscle mass, larger areas for flight muscle attachment and higher linearized wing loadings. Strigiformes had a pectoral muscle mass only half the size of that of attacking Falconiformes and had a correspondingly smaller sternum area. A skeletal body‐size measure was determined to enable calculation of intestine length independent of body‐size and shape differences. Attacking species have a small intestine which is 20–30% shorter than would be predicted on the basis of body‐size and 50% shorter than found in searchers of equivalent body‐size. Strigiformes that locate prey by active flight also have intestinal tracts shorter than expected. The likely effects of intestine length on digestive efficiency and food utilization are discussed and it is suggested that, in predatory birds, some species have evolved alimentary tracts that are shorter than necessary for maximum digestive efficiency in order to e

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb01564.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

This study describes the sexual behaviour of the adult male and female tammar wallaby from the time a female gives birth to the end of post‐partum oestrus. Eleven females were continuously observed from around the time of birth until up to 3 h after the last observed mating attempt. Males began to associate with females from around the time of birth, thus females appear to be attractive to males at, but not prior to parturition. Females subsequently allowed males to mate with them from 1.3±0.8h (mean±S.D.) post‐partum, although the first ejaculation was delayed until 1.8±0.8h after birth owing to intense intermale aggression directed towards any male which attempted to mate with an oestrous female. Mating chases, in which a post‐partum female was pursued by several males, were observed from 1.3±0.8h post‐partum. All of this mating activity usually occurred within the first 6h

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb01565.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Population size and emergence order ofR. aegyptiacuswere studied in the Abas cave. Haifa, Israel. Throughout the reproductive period adult females populated the cave and the adult population consisted mainly of adult females except during winter when higher numbers of adult males were recorded. The proportion of juveniles increased consistently from spring to winter. Thus, it is suggested that the Abas cave serves as a maternity roost. Adult females in the reproductive state emerged from the cave earlier that juveniles and adult males. Social factors and differences in nutritional demands which may correspond to this different emergence order are discussed.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb01566.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY