http://en.wikipedia.org/wiki/American_Kestrel
The bird you are describing is likely the American Goldfinch, which has a bright yellow body and black wings and cap, especially in males during the breeding season. Another possibility is the Yellow-headed Blackbird, which features a striking yellow body and black wings. Both birds are known for their vibrant colors and are found in North America.
It sounds like you are probably talking about the American Goldfinch. They have black feathers on most of their head, yellow bodies, and black and white feathers on their wings.
Oriole
The Orchard Oriole is primarily a vibrant yellow and black bird. Males feature a bright orange-yellow body with black wings and a black head, while females are generally more subdued, displaying a yellow-green coloration with lighter underparts. Their striking colors make them easily recognizable among other bird species.
the bird is called an American goldfinch. we have a billion of them and they love thistle.
It is a male Goldfinch.
It sounds like you are probably talking about the American Goldfinch. They have black feathers on most of their head, yellow bodies, and black and white feathers on their wings.
Chickadee
The bird with blue wing feathers in Greece is called a Blue Winged Teal. It has cinnamon brown body feathers and patterned black marks on it.
Oriole
If you mean this bird... http://i.pbase.com/g3/25/702225/2/66725286.iFSy8Spx.jpg then it is a baby Cedar Waxwing.
contour
This type of bird is a vulture. Vultures usually have black feathers, though, not brown.
That would be the Black Headed Oriole.
Feathers.
That depends on a lot of factors. Is it a wild or domesticated bird? If wild, what is the location, nest structure if visible, etc. Immature birds are sometimes difficult to identify until they start to acquire their adult plumage. But it could possibly be a yellow finch, depending on the location. It was on our patio with yellow tail feathers, a olive green body and a black crest on it's head. There were 4 of them in our bird bath
The kiwi bird is a unique bird that has hair-like feathers on its body.