Background: The foraging and diving behavior of waterfowl are affected by a number of important factors. Hence, learning more about these major factors is of great concern in order to protect endangered species. In th...Background: The foraging and diving behavior of waterfowl are affected by a number of important factors. Hence, learning more about these major factors is of great concern in order to protect endangered species. In this study, we verified the effect of sex, temperature, time and flock size on the diving behavior of the Scaly-sided Merganser(Mergus squamatus).Methods: The study was conducted by means of focal animal sampling in the Wuyuan section of the Poyang Lake watershed in Jiangxi Province, China from December 2015 to March 2016. We used one-way ANOVA and LSD tests to investigate the differences among these factors. Pearson correlations were used to test the relation between pause duration and the previous or subsequent dive duration. The relations between these factors and dive/pause duration are illustrated using Spearman correlations.Results: Mean dive duration and mean time on the pause of males were significantly higher than those of females. With an increase in temperature, dive duration significantly increased. Along with the passage of time of year and daytime, dive duration significantly increased, while dive duration decreased significantly with the increase in flock size.Conclusions: Sex, temperature, time and flock size have an effect on the diving behavior of the wintering Scalysided Merganser. The difference of diving behavior between males and females is related to differences in body mass. The difference of diving behavior among various temperatures and time periods may be related to a low minimum rate of oxygen consumption, while the difference among various flock sizes may be caused by rising intraspecific competition.展开更多
The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied.The primary aim of this study was to identify ...The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied.The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond,individually and as groups,to the relative abundance of prey around a fish farm.Detailed views of dolphins' behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data.A total of 2150 dive intervals were analyzed,corresponding to 342 focal samples,lasting over 34 hours.Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds.This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area.This study's results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding,dolphins did not modify dive duration.Additionally,underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities.Thus,bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey.When top predators display behavioral responses to activities not directed at them,the task of studying all possible effects of human activities can become even more challenging.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31560597)
文摘Background: The foraging and diving behavior of waterfowl are affected by a number of important factors. Hence, learning more about these major factors is of great concern in order to protect endangered species. In this study, we verified the effect of sex, temperature, time and flock size on the diving behavior of the Scaly-sided Merganser(Mergus squamatus).Methods: The study was conducted by means of focal animal sampling in the Wuyuan section of the Poyang Lake watershed in Jiangxi Province, China from December 2015 to March 2016. We used one-way ANOVA and LSD tests to investigate the differences among these factors. Pearson correlations were used to test the relation between pause duration and the previous or subsequent dive duration. The relations between these factors and dive/pause duration are illustrated using Spearman correlations.Results: Mean dive duration and mean time on the pause of males were significantly higher than those of females. With an increase in temperature, dive duration significantly increased. Along with the passage of time of year and daytime, dive duration significantly increased, while dive duration decreased significantly with the increase in flock size.Conclusions: Sex, temperature, time and flock size have an effect on the diving behavior of the wintering Scalysided Merganser. The difference of diving behavior between males and females is related to differences in body mass. The difference of diving behavior among various temperatures and time periods may be related to a low minimum rate of oxygen consumption, while the difference among various flock sizes may be caused by rising intraspecific competition.
基金Funding for this research came from the Bottlenose Dolphin Research Institute-BDRI and private donations
文摘The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied.The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond,individually and as groups,to the relative abundance of prey around a fish farm.Detailed views of dolphins' behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data.A total of 2150 dive intervals were analyzed,corresponding to 342 focal samples,lasting over 34 hours.Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds.This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area.This study's results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding,dolphins did not modify dive duration.Additionally,underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities.Thus,bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey.When top predators display behavioral responses to activities not directed at them,the task of studying all possible effects of human activities can become even more challenging.
