There are thousands of different kinds of birds and this is not enough for identification.
It would help to know: What kind of bird? How large? In what country was it found? What type of habitat? What sound did it make?
The answer is a Western Kingbird.
i would say it is a cardinal
A mallard is a bird that has an iridescent green head and brown on the body. The ring necked pheasant is another bird with a brown body, and an iridescent green head.
The small bird with a yellow belly and black head is called a Yellow-bellied Flycatcher.
I think it's a parrot.
The bird species known for having a yellow belly and a black head is the Yellow-headed Blackbird.
love bird
The Eurasian Blackbird is a black bird with a yellow beak.
the bird is called an American goldfinch. we have a billion of them and they love thistle.
If you live in Europe it could quite possibly be a redwing.
Chickadee
the bird your looking for is the eastern meadowlark