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Grassland Bird Monitoring

Oakwoods Metropark Grassland Bird Monitoring Report

by Ryan Colliton

Natural Resources Coordinator, Huron-Clinton Metroparks


Year two of breeding bird monitoring was a success!  Through the month of June and part of July dedicated and knowledgeable volunteers rose before the sun and surveyed the grasslands at Oakwoods Metropark.  We can’t thank the volunteers and Detroit Audubon Society enough for all their dedication helping us organize and execute this program.  This data set along with others (e.g. floristic inventories) will be used to determine best courses of action when managing the grasslands at Oakwoods Metropark.

So what conclusions can we make with two years of data?  We need to be careful about making too many conclusions at this point.  Natural communities are dynamic and changes seen from year to year can be the result of many factors and not necessarily habitat changes. It is important to continue monitoring annually so we can establish species population trends as opposed to making decision and acting on them based on one to two years of data.  Using multiple years of data will also help us minimize the impact of the individual on the data.  This is something that many people don’t th11412043_10102333744684044_3816814103838010542_oink about when looking at data sets.  The data whether intentionally or not is affected by the person collecting it.  For instance, some surveyors may be better at identification through song and others by physical characteristics these and many other factors affect the collected data which is why it is important to use data to identify trends overtime and not just use data from a single year.

Based on USFWS literature which was used to develop this program these are the characteristics of our avian communities we can begin to classify with two years of data, however, I believe the more years of data we have the more accurate our assumptions about the bird community will be:

  •       Species presence/absence
  •       Locally rare species
  •       Species richness
  •       Relative abundance

We experienced some changes in species presence and absence from 2015 to 2016.  Most notably was the new account of the State Endangered Henslow’s Sparrow.  Two observations of Henslow’s occurred in 2016.  Eastern Meadowlark numbers were lower this year than last (11 to 5, respectively.)  Alder Flycatcher was also a new account this year and was found using the shrub thickets around the old agricultural drains in the park.  Based on the data it is also safe to assume that Henslow’s Sparrow would be considered a locally rare species which follows the overall trend in Michigan grassland habitats. Species richness increased from 2015 to 2016 from 39 recorded species to 54 in 2015.

So where do we go from here?  It is my hope that this program will continue and expand as long as there is interest from the birding community to participate.  In fact, because 2015 was such a success we expanded the program to our coastal marshes at Lake St. Clair.  We will review what our needs our and see which new location would be the next best place to establish survey sites.

As we continue to manage the grasslands at Oakwoods we will continue to have the need for experienced people to monitor the bird populations.  At the moment, we are focused on reducing invasive shrub coverage and promoting native grasses and wildflowers at the bird monitoring sites.  It is our hope that this work will result in the return of stable populations of some of our declining grassland species, especially those identified in the new Michigan Wildlife Action Plan, these include the Northern Bobwhite, Henslow’s Sparrow, Dickcissel.  We will have to wait and see and we will need your continued support to collect this data – because if no one is looking for them, how will we ever know?

Thank you again to the Detroit Audubon Society and volunteers for all your hard work.  It is because of your efforts that the Huron-Clinton Metroparks will be able to make more informed decisions when it comes to the management of your Metroparks’ Natural Resources.

If you would like to become a monitor for this upcoming field season, please contact our Research Coordinator at alandgraf@detroitaudubon.org.