Successful restoration of degraded tropical lands will provide habitat not only for numerous resident species but also for migratory species.  Neotropical migrant birds are a group of conservation concern because of their apparent vulnerability to habitat degradation on their nesting grounds, migratory routes, and wintering grounds.  Thirteen restoration sites in southern Costa Rica were planted in 2004 through 2006 with four native or naturalized plant species in three treatments:  1) plantations where seedlings were planted in rows, 2) islands where seedlings were planted in patches, and 3) controls where seedlings were not planted.  Sites were cleared of vegetation (aside from the planted seedlings) for the first two and a half years after planting so that seedlings could become established.  We sampled Neotropical migrants in the sites in February and November 2006 and 2007.   We also conducted behavioral observations of foraging migrants during 2007-2008 in one of the planted species, Inga edulis, in the plantation and island treatments.  Our objectives were to 1) determine whether time since planting and planting treatment influenced the likelihood of Neotropical migrants being detected and 2) document the resources in Inga edulis that were used by Neotropical migrants.

Results/Conclusions

We detected 22 species of Neotropical migrants in the sites.  The most commonly detected were the Tennessee warbler, Vermivora peregrina, the mourning warbler, Oporornis philadelphia, and the chestnut-sided warbler, Dendroica pensylvanica.  Migrants were most commonly detected in the oldest sites (planted in 2004) and in the plantation treatments.  When clearing was ended, the establishment of non-native grasses, particularly Pennisetum sp., in some of the sites appeared to diminish their suitability for Neotropical migrants.  Behavioral observations of migrants in Inga edulis showed that they foraged for arthropods and took nectar from flowers and extrafloral nectaries.  Our results indicate that active restoration of degraded tropical lands improves the likelihood they will provide habitat for Neotropical migrants and that some planting designs provide habitat more quickly than others.  In addition, characteristics of plant species used for restoration, such as the presence of extrafloral nectaries, may enhance their usefulness to migrants.