<P> Frequently referred to as "Pollard Transects" or "Pollard Walks" in North America, a transect is a protocol designed to standardize the recording of butterfly observations, the initial format was outlined by Ernie Pollard in 1977 . The transect protocol involves one observer walking a fixed path at a constant pace, multiple times in a season . Butterflies are counted when they are seen within a prescribed distance from the path, often 2.5 meters on either side of the path, and only when the butterflies are seen in front of, or above, the observer (i.e., no backtracking). A second person may work with the observer to identify and / or photograph insects spotted by the observer . Transects should not change from year to year and ideally should sample a variety of habitats . </P> <P> Examples of long - running restricted searches are Art Shapiro's Butterfly Project in the US (started in 1972), and the UK Butterfly Monitoring Scheme (started in 1976). </P> <P> Open searches, also sometimes referred to as "checklist searches", are intended to focus on the presence and abundance of butterflies in a given area . They can be single events such as the North American Butterfly Association's July 1 and July 4 counts in Canada and the U.S. respectively, or they can be regular or ad hoc counts conducted by individuals or groups . The lack of formal structure makes them suitable for many citizen science programs . </P> <P> In terms of the relative outcomes or the efficacy of open vs. restricted searches, studies have shown that open searches are more likely to find a greater number of species in a given area . Royer, et al. note that one reason for this is that during an open search, the "observer is free to search out places where butterflies typically would breed or congregate" rather than follow the fixed path of a transect . </P>

When does the north american butterfly association count butterflies in the u. s. each year