HOW NATIONAL PARK MANAGEMENT AND CHANGING MOOSE POPULATIONS AFFECT BIRD COMMUNITIES IN THE GREAT LAKES REGION

Twice each year, billions of birds--over 325 species and approximately 40% of migrating shorebirds and waterfowl in North America--fly through the Great Lakes region. This area is part of the Mississippi Flyway, a huge bird migration route from the warm wintering grounds of Central and South America to the birds' summer breeding sites up north.

Because the Great Lakes are such an important stop in this bird migration, many of the nearby national parks have been monitoring the annual bird populations for decades. For example, Isle Royale National Park in Michigan has conducted thorough breeding bird surveys every year since 1994. Recently the Great Lakes Inventory and Monitoring Network (GLKN) has combined these local efforts into a unified, regional system.

In this study, we compare bird communities across time and between the regional parks using Bayesian Hierarchical Modelling of Species Communities (HMSC). Additionally, we use deep time-series data from Isle Royale National Park to examine their bird community's reaction to the island's exploding moose population and extensive understory moose-browse.

We find that the presence and absence of many bird species in these parks follow continent-wide trends in population loss. We also find strong variation between bird communities in different parks. As for Isle Royale's increasing moose population, although it can help predict the presence of several bird species, we find no radical shifts in community composition as a result.