Monarch butterflies (Danaus plexippus) in eastern North America must make frequent stops to rest and refuel during their annual migration. During these stopovers, monarchs form communal roosts, which are often observed by laypersons. Journey North is a citizen science program that compiles roost observations, and we examined these data in an attempt to identify habitat characteristics of roosts. From each observation we extracted information on the type of vegetation used, and we used GIS and a national landcover data set to determine land cover characteristics within a 10？km radius of the roost. Ninety-seven percent of roosts were reported on trees; most were in pines and conifers, maples, oaks, pecans and willows. Conifers and maples were used most often in northern flyway regions, while pecans and oaks were more-frequently used in southern regions. No one landcover type was directly associated with roost sites, although there was more open water near roost sites than around random sites. Roosts in southern Texas were associated primarily with grasslands, but this was not the case elsewhere. Considering the large variety of tree types used and the diversity of landcover types around roost sites, monarchs appear highly-adaptable in terms of roost site selection. 1. Introduction Research on one of the world’s most famous insects, the monarch butterfly (Danaus plexippus, Figure 1), has benefitted greatly from numerous citizen science programs in North America devoted to tracking this species at various life stages. The attention given to this insect no doubt stems from its large size, easily identifiable orange and black colors (Figure 1), and its well-known and spectacular migrations, which are unique among butterflies. All of these factors make this butterfly extremely charismatic, and this helps to promote public participation in various citizen science programs. For example, the larval stages of this insect are monitored each summer by volunteers of the Monarch Larval Monitoring Project (http://www.mlmp.org/), and these data have been used to document geographic and temporal variation in population recruitment [1, 2]. In the western North American population, volunteers count numbers of adult monarchs that overwinter in clusters along the California coast (Western Monarch Thanksgiving Count), and a recent analysis of these data showed the importance of climatic conditions at the natal sites for predicting overwintering numbers [3]. There is another citizen science program whereby volunteers submit samples of a monarch-specific protozoan parasite
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