Vegetative associations of wood warblers migrating along the Middle Rio Grande Valley, New Mexico

We examined abundance and richness of wood warblers among vegetation types at the Bosque del Apache National Wildlife Refuge and the Rio Grande Nature Center in the Middle Rio Grande Valley of New Mexico. Rarefaction analysis indicated that there were marginally significant differences in species richness between sites. In spring, wood-warbler richness was greater at the Bosque del Apache than at the Nature Center. This pattern reflected the greater likelihood of catching uncommon migrants at the Bosque del Apache than at the Nature Center. The same seven species were most common at both sites although their order of abundance differed between sites. Capture rates of these species were greater at the Nature Center than at the Bosque del Apache in the fall, but not during the spring. In general, variation in capture rates among vegetation types was greater in the Bosque del Apache than in the Nature Center. In particular the capture rates in willow were greater than in other vegetative types.