Tuesday, June 22, 2010

Mowing and grassland birds

I became interested in mowing and the Indiana University cross country course after reading a 2007 Audubon magazine article on common bird species in decline. Species #6 on that list was the Eastern Meadowlark, with a population decline of 72% since 1967. The major reason for this decline is the destruction of grassland habitat.

This started me thinking about my experience with the XC course. Each spring the grass would sprout up and provide good nesting sites for meadowlarks. After the meadowlarks nested, IU would mow the XC course, destroying the nests. Most birds would leave. The ones dumb enough to stick around and re-nest invariably had their nests destroyed by subsequent mowing. The net result is that meadowlarks were rare on the XC course.

After two years of not mowing the bulk of the XC course, there’s a healthy meadowlark population there now. Yesterday I was trying to count meadowlarks by sight and by listening for songs and calls. They were especially vocal yesterday, and I counted at least 15. That’s probably a conservative estimate, as I was trying hard not to double count and probably missed some birds.

Field Sparrows are #9 on the Audubon “common birds in decline” list, with a population decrease of 68% over 40 years. Field Sparrows were rather unusual on the XC course when I started birding there five years ago. Now they are common. It’s not unusual to hear several birds sing simultaneously. Yesterday I noticed 10-12 of them.

As I birded the XC course yesterday I was struck by the diversity of plant species. When I first started walking the XC course it was pretty much a monoculture. Pretty much one species of grass, mowed frequently. Today the plant life is varied. I’m no expert on ID’ing grasses, but I’d estimate there are at least a dozen species...some native, some not. Anyway, I was thinking it would be pretty cool if someone were to do a botanical survey of the XC course and develop an inventory of the plant life there. Might make an interesting class project for some IU students, and it would be useful in the future for when IU gets around to planning for the management of this grassland area. Any takers?

1 comment:

  1. Delaying mowing until after nestlings have fledged is one of the "101 Ways to Help Birds" I wrote about in my book of the same name. But people are just too apathetic--maybe too besieged by problems hitting from every direction--to want to read a book about conservation. I hope you have more luck publicizing the issue than I have!