The BTBW age ratio (% older) did not differ significantly between plot types (Kruskal-Wallis test: k = 2, [chi square] = 0.
used by nesting BTBW in other parts of the species' range (Holmes 1994) do not occur in most Great Lakes forests, and we suggest that at sites like ours, where most of the understory comprises regenerating tree species, balsam fir can play a role similar to that of hobblebush, particularly in areas where deer browsing reduces the abundance and heights of deciduous species.
BTBW densities in our study area, which is near the western edge of the species' range, were low compared to those in more central parts of their range (e.
We suggest that this difference in height distribution is likely an important driver of the positive BTBW response to balsam fir at these sites.
Our results indicate that stem density of balsam fir understory predicted BTBW abundance in deer-browsed forests of northern Michigan.
05); between-plot differences in the ratio of older to younger male BTBWs were not significant (Kruskal-Wallis test, P = 0.
In addition to nesting in both balsam fir and deciduous cover < 1 m tall, BTBWs often nested in the lower branches of balsam firs that were 1-2 m high (LJK and KRH pers.
1996) found that areas with more understory had greater densities of BTBWs and greater proportions of older birds.