Bad Year for Birds at Barr Lake

In the third week of September I visited the Banding Station at Barr Lake operated by the Bird Conservancy of the Rockies. This is one of two sites where the BCOR bands and monitors birds migrating through the area in spring and fall.

I checked in and took a seat on a shaded deck along the shore of the lake that acts as the bird banding station. Not long after I had a seat. , the volunteer coordinator Meredith McBurney appeared on the deck and apologized for not having a single bird in their mist nets to show us that morning. (What is Bird Banding?)

“It’s a bad year for birds here” she explained.

“Why?” was the obvious question the other participants on the bench beside me wondered outloud.

It Started With Fires in Canada

“Well, The first factor we must consider are the fires up in Canada earlier this year.” She began. Canada is the destination for a good portion of the warblers passing through Colorado in the spring. So, these little birds flew thousands of miles to migrate to nesting grounds only to inhale unhealthy smoke and find their habitat burning. Not surprisingly, few were able to breed and those that did were compromised by the bad air and lack of insects due to the fires.

The second thing to consider is that we had a cold spring. Because of this, plants and insects were delayed by the temperatures. And this had an adverse effect on the habitat. “It even affected local birds like Chickadees.” She said.

Thirdly, the reservoir (Barr Lake) held water at higher levels than usual for much longer during the spring. This stunted the growth of the Smartweed (Persicaria lapathifolia) that grows along the waters edge. She said that usually by early spring the plants are knee high, pointing out to a patch of low growing browning plants. Unfortunately, they never got bigger than that she said, and they turned brown. This was much loved sparrow habitat. “We hardly saw any sparrows this year. Where are all the sparrows?” She asked.

Impromptu Warbler Workshop

Then she invited us to take a short walk to see the mist nets they had set up to catch the birds. The nets are made of fine mesh that blends in with the surroundings. They set them up in between habitat so the bird will fly into it going from one set of vegetation to the other. The bird banding volunteers and employees check the nets every 30 minutes, so the little birds aren’t vulnerable to predators.

Unexpectedly, as we walked past a net, a little yellow and black bird flew into the mesh and was caught. Everyone was excited that they got to see the net in action. Meredith collected him safely from the net. It was a male Wilson’s Warbler, who they had banded the previous day. After we took him up to the banding station, Meredith gently blew on the birds feathers to estimate the fat on the bird. Additionally, she weighed him, wrote down his band number and then he was let go.

We got to see three other warblers that morning, which was fun but a far cry from usual numbers of birds BCR has seen in past fall migrations.

Will Things Look Up Next Year?

Maybe.

However there is a fourth factor and that is the company that owns Barr Lake, Farmers Reservoir and Irrigation Company (FRICO) is removing trees and vegetation along the lake in order to fix leaking berms. The project started this year and will start up again in the spring.

The banding station has been at Barr Lake for 35 years and has bird banding data that goes back that far. Meredith and her group will be able to tell in the future if there continues to be bad years for birds.