From 2008–2010, as part of an ongoing inventory of assemblages of cavity-nesting wasps and bees of the Finger Lakes region of central New York State, we conducted trap-nest surveys at sites administered by the Finger Lakes Land Trust (FLLT): the Roy H. Park Preserve (RPP) and the Dorothy McIlroy Bird Sanctuary (DMS). Over 200 nests were provisioned by 21 species, including 12 species of wasps and 5 species of bees at RPP and 14 wasps and 2 bees at DMS. Twelve species nested at both sites, but the most common at RPP (Trypoxylon frigidum Smith, Osmia pumila Cresson, and Megachile relativa Cresson) were not among those most common at DMS (Trypoxylon lactitarse (Saussure), Ancistrocerus antilope (Panzer), Passaloecus cuspidatus Smith, and D. sayi sayi Banks). The greater species richness of bees at RPP was also reflected in a greater ratio of bee- to wasp-provisioned nests. One or more natural enemies also emerged from ∼ 20% of nests, five species of brood parasites, three parasitoids, and two that we assumed are incidental cleptoparasites. The most common species of natural enemies was Caenochrysis doriae (Gribodo), which emerged from over half of T. frigidum nests and nearly one-quarter of its nest cells. Bees tended to produce more offspring per nest, partly because of higher levels of parasitism on wasps. We compare the results to that of an earlier survey we conducted at the Montezuma Wetlands Complex located northwest of the FLLT sites.