Dispersal is a fundamental ecological process that can be affected by population density, yet studies report contrasting effects of density on propensity to disperse. In addition, the relationship between dispersal and density is seldom examined using densities measured at different spatial scales or over extensive time series. We used 51 years of trapping data to examine how dispersal by wild deer mice (Peromyscus maniculatus) was affected by changes in both local and regional population densities. We examined these patterns over both the entire time series and also in 10-year shifting windows to determine whether the nature and strength of the relationship changed through time. Probability of dispersal decreased with increased local and regional population density, and the negative effect of local density on dispersal was more pronounced in years with low regional densities. In addition, the strength of negative density-dependent dispersal changed through time, ranging from very strong in some decades to absent in other periods of the study. Finally, while females were less likely to disperse, female dispersal was more density-dependent than male dispersal. Our study shows that the relationship between density and dispersal is not temporally static and that investigations of density-dependent dispersal should consider both local and regional population densities.

分散是一个基本的生态过程，会受到人口密度的影响，但是研究报告了密度对分散倾向的不同影响。另外，很少使用在不同空间尺度或广泛时间序列上测得的密度来检查扩散与密度之间的关系。我们使用了51年的诱捕数据来研究野鹿小鼠（Peromyscus maniculatus）受到本地和区域人口密度变化的影响。我们在整个时间序列中以及在10年的变动窗口中研究了这些模式，以确定这种关系的性质和强度是否随时间变化。分散的概率随着局部和区域人口密度的增加而降低，并且局部密度对分散的负面影响在区域密度较低的年份中更为明显。此外，负密度依赖性分散的强度随时间而变化，范围从几十年的极强到研究的其他时期都没有。最后，尽管雌性散布的可能性较小，但雌性散布比雄性散布对密度的依赖性更大。