Just scare it away OR you can build another bird feeder This is not an answer. We have several feeders and they fly to all of them and keep all the birds away. Obviously you're not an expert. According to the staff at WBU--stop using black oil sunflower seeds--in fact clean out the feeders to no smell or residue is left. I did this and almost all my cowbirds are gone. They are feeding on what they find that was left on the ground. I had dozens and now it is down to a couple every now and then
Cowbirds lay their eggs in other birds nests, leaving the young to be raised by the host species.
the cowbirds work with the other birds
In North America, cowbirds do this. In Europe, it is a type of Cuckoo that does this.
Cowbirds lay their eggs in other birds nests.http://www.illinoisraptorcenter.org/cowbirds.html
Cuckoos and cowbirds are famous for laying their eggs in other birds' nests, and leaving the chicks to be raised by the other birds.
No Finches will gather with other birds at feeders and the feeder can be placed with other species specific feeders.
Cowbirds follow herds of bison to catch and eat the insects that are stirred up from the bison's feet. there are other bugs and flies that are attracted to the animal. The bison allow the birds to sit and rest as they guard them from the pests. It is what is called a symbiotic relationship.
Cuckoos and cowbirds lay their eggs in other birds' nests, and leave them for the other bird to raise. Weavers and whydahs (African species) also do this.
The cowbirds remove ticks from the bison, while the bison disturb insects that are picked up by the birds.
Some species, like cowbirds and other blackbirds, feed on the insects and worms turned up by the plough.
Cowbirds are considered unusual because they practice brood parasitism, where they lay their eggs in the nests of other bird species, letting those birds raise their young. This behavior can harm the host bird species by outcompeting their offspring for resources. Additionally, cowbirds have evolved to follow large mammals like buffalo in the wild, exploiting the insects stirred up by their movement.
Egrets, aka cowbirds, eat insects. The young birds are fed by their parents, just as other bird species are. The parents feed on the insects, then regurgitate the food into the baby bird's open mouths. That is why a baby bird will raise its head and open its mouth wide when they sense, feel, or see movement above them.