Thursday, October 30, 2014

Regrouping on Meadow-nesting Bird Habitat

Between a pasture and a crop circle
Since 1997, our organization has been working diligently to create habitat for meadow-nesting birds which, as a group, are the most endangered suite of birds on the East Coast because of habitat loss.  Our strategy has been to establish native, warm-season grasses on a 160-acre farm we purchased that year.  Now nearly two decades into the project, we have a fairly respectable stand of native "prairie" grasses cloaking the land.  The grasses are beautiful (especially this time of year), resilient, and very popular with our visitors - but not with the birds we are trying to attract.  Eastern Meadowlarks, Bobolinks, and several species of sparrows stop in the grasslands during migration, but they never stay to breed.  What's wrong?  Didn't we do everything right?

Well, it turns out we didn't do everything right.  Grassland managers all along the East Coast have come to realize that the birds are seeking diversity - diversity in height and diversity in plant composition.  To the birds, our grasslands are too dense, too tall, and too monotonous, and they don't provide food (i.e., insects) in sufficient quantities for nestlings.

So, you might recommend that we diversify the grasslands, and you'd be right.  However, we also have a terrible problem with invasive plants.  The grasses can be treated with special herbicides that kill all invasive plants except the grasses, but there's no such "magic bullet" for diverse combinations of plants.  Once invasive plants colonize a mixed-vegetation meadow, control becomes much more time consuming and costly because the invasive plants have to be removed "surgically" without disturbing the desirable plants.  We've resisted trying to diversify our grasslands for that reason.

But, we've finally come to the realization that (1) we're not going to attract meadow-nesting birds if we don't do something different, and (2) if we can't attract meadow-nesting birds, why have the grasses at all because our landscape really wants to be a forest and we have to fight Mother Nature (i.e., natural succession) to keep it in grassland.

Fortuitously, I invited a respected field ecologist to speak to my restoration ecology class a few weeks ago about native grasslands.  This ecologist and I are good friends, and he has visited my preserve to consult on several occasions.  He also serves on the board of directors of another land trust in the region.  He told me that "his" land trust had had Eastern Meadowlarks nesting in native grasslands this summer, and he suggested that I talk to his land manager for some guidance.  So, I rounded-up my senior stewardship staff for a field trip and we paid a visit to the other land trust on October 30.  
Edge of the "crop circle" (darker foreground), native grassland (tawny center) and pasture (green, far left)
Tom, the preserve's land manager had successfully created native grasslands like we had, but had also failed to attract meadow-nesting birds.  Then, he decided to create "crop circles" - round meadows within the grasslands that he seeded with a mixture of 16 different species of low-growing flowering plants (i.e., wildflowers).  Three years ago, he established about 10 such circles ranging in size from 0.25-acre to over 4 acres.  And, this summer, Eastern Meadowlarks nested in his preserve - not in the crop circles (and not in the native grasses), but in a pasture composed of non-native grasses immediately adjacent to the largest crop circle.  
Diverse crop circle vegetation (foreground)
Tom watched the meadowlarks build nests in the pasture (which is just as monotonous a monoculture as the native grasslands, but lower in height).  Then he watched the adult birds fly into the crop circle to catch insects that were using the wildflowers.  Success!
Crop circle (foreground), native grasslands (mid-ground), and woodland (background)
Tom's crop circles get colonized by the same invasive plant species with which we have to contend, but he told us that he is able to control the invasives before they become problematic with a combination of mowing before the invaders set seed, spot application of herbicide, and the judicious use of a string trimmer.  He's got a smaller land stewardship staff than I do, so my staff should be able to do as well.
Crop circle (right) and native grassland (left)
My staff drew-up plans for our grassland modifications in the car on the way back to my preserve.  Stay tuned; it may be a year or two before we're successful, but at least we now have a plan!
Autumn color in the grasslands


John "By Stargoose And Hanglands" said...

This sounds very similar to the "skylark plots", which are undrilled patches left within arable fields for the benefit of the birds. Again the skylarks don't use these patches for nesting but for feeding. You can read about it here:

packrat said...

The thing I really like about your blog, Scott, is that I often learn something really interesting from reading it. Who would have thought that potential nesting birds would be so particular about "sameness" in a grassland? Tom--that's who. Brilliant use of the human noodle to figure that out. Hope your preserve has similar success in the near future.

Mark P said...

It's pretty cool that you found someone who has actually had success attracting nesting birds.

Scott said...

John: Thanks for the RSPB link! The "skylark plots" are very similar. I'm going to add the RSPB article to my arsenal to convince naysayers as we move forward--if necessary!

Scott said...

Packrat: My wife Kali has been badgering me for years about what she calls "birdie bed-and-breakfast": give the birds an appropriate place to nest (the bed) and fields in which they can look for insects (the breakfast). Our dense and tall native grasses are not to the birds' liking (as I've come to learn) and the grasses don't support enough insects (though they seem to be full of insects to me). In any case, she was right all along (aren't wives always right?). Now, we have what could be a manageable way to set-up the B&B.

Scott said...

Mark: The local birders know where to find meadow-nesting birds, and they're usually in farmers' cool-season grass (i.e., non-native) pastures. But, we'd been pushing our native grass strategy for so long it's hard to let go. Plus, we do still have some cool-season (non-native) pasture on our farm, but the birds never used it, which I guess is another reason we weren't so quick to focus on the pasture grasses as habitat. Clearly, we've got to have a mix like Tom created.

robin andrea said...

I love the evolution of ideas, invention, and instinct on this. The work being done to help the native bird species is truly fantastic. I can't wait to see future updates on this plan. Excellent!

Scott said...

Thanks, Robin Andrea. I can't wait to see the results myself. It took three year5s at Tom's preserve, so I may not have success immediately. Stay tuned!