Many territorial avian species, including the federally-endangered Cape Sable seaside sparrow (Ammodramus maritimus mirabilis), tend to aggregate breeding territories often using conspecific cues to select habitat. Species that tend to have naturally low densities may benefit greatly by clustering territories by reducing potential Allee effects. We formulated two competing hypotheses regarding the use of conspecific cues by Cape Sable seaside sparrows in the selection of breeding habitat: (1) sparrows may use early-season song as a cue to select breeding habitat during the current year, or (2) sparrows may use late-season song as a cue to select breeding habitat in the following year. We designed a conspecific song playback system to test if Cape Sable seaside sparrows use conspecific cues to select breeding habitat and to determine whether sparrows would respond to such a management manipulation. We broadcast sparrow song in suitable habitat early and late in the 2009 breeding season to encourage recruitment of sparrows into previously unoccupied habitat. We conducted point count surveys throughout the breeding season to measure sparrow response. Point count data were analyzed using generalized linear models.
Results/Conclusions
Our preliminary results were promising; we observed evidence that Cape Sable seaside sparrows used conspecific cues in the selection of breeding habitat and we documented that sparrows respond to song playback as an artificial conspecific cue. Our findings have important management implications since habitat restoration alone may not be enough to encourage recruitment and settlement by Cape Sable seaside sparrows into newly restored habitat in the Florida Everglades due to an absence of conspecifics. Additional sparrow surveys are planned for the 2010 breeding season to determine if sparrows recruit into areas where late-season song was broadcast during 2009. Further experimental use of conspecific playback is also planned for the 2010 breeding season to obtain better estimates of sparrow response.