The report from years ago regarding the state of Tri-colored blackbird (Agelaius tricolor) populations in California was foreboding. The message was clear: populations of Tri-colored blackbirds are in trouble, and as one of the NBHCP’s 22 “Covered Species,” the Conservancy has a particular interest in this matter.
One of the typical remedies for Tri-colored blackbird population decline found on the web is to restore marsh habitat. The Conservancy has many hundreds of acres of that. Also noted is that the birds feed on ripening rice grain in rice paddies. The Conservancy has thousands of acres of that.
We believe that the most likely limiting factor is a notable reduction in large insects. Our sources note that Tri-colored blackbirds feed on grasshoppers, dragonflies, moths, butterflies and similar prey. We used to see these larger insects in abundance in the Basin. Twenty or so years ago, after a morning on the preserves, the windshields on our vehicles used to be splatted with insects. That is rare now.
Urbanization, mosquito control efforts, the use of insecticides in agriculture and in residential property care, drought conditions and others are suspect for the decline in prey production for Tri-colored blackbirds.
In the photo above, we see two blackbirds. A typical Red-winged blackbird (Agelaius phoeniceus) is seen at the top of the photo and a Tri-colored blackbird is below. In the photo below, we see two Tri-colored blackbirds, one resting and the other in flight. These photos were taken on a Conservancy managed marsh in the Natomas Basin.
We are very happy to see our friend the Trike (common nickname for the Tri-colored blackbird) using the preserves. We’d like to make sure they are well fed. That requires more availability of its primary prey. We are working on that.