It's that time of year when it can really be difficult to ID some birds. The reason is that fledglings (birds that have recently left the nest) often look very different from their parents. So it is especially important to consider size and shape first before considering coloration when making ID's at this time of year. When I say size and shape, I mean how the bird looks in general. Fledglings of most birds are fully grown when they leave the nest. Their feathers may not yet be of full length, but in terms of body size, they will be the same size as their parents. In fact, fledglings are often heavier than their parents right after they leave the nest. This is believed to be a benefit in helping young birds survive before they are fully capable of feeding themselves.
There are many birds that pretty much look exactly the same as their parents when they fledge. Titmice, Chickadees, and Nuthatches all pretty much take after their parents. However, other birds such as Cardinals, Woodpeckers, Robins, Bluebirds, and Mourning Doves can look quite different. Young Starlings and Grackles will look very different, too.
Here are some tips for ID'ing those youngin's:
Young Cardinals will have dark colored bills instead of the bright orange bill characteristic of an adult. The bill color will get progressively more orange as time goes on until about November when it will be fully orange. Young male Cardinals will also be changing colors right about now. They will start to molt out of their drab brown and begin to show signs of a brighter red. This, too, will take place over time, so keep that in mind when ID'ing your birds.
Young Robins and Bluebirds will sport spots on their breasts when they are young. Their true colors will appear over time just as in Cardinals. Eventually, the spotted breast will give way to that reddish color we all know and love making their appearance kind of a half and half for awhile.
Woodpeckers will look similar to their parents, but be much more brown in color until they molt the brown and replace it with black. Other species are similar regarding the amount of brown in their feathers. In fact, this is true with all of the blackbirds such as Grackles, Starlings, and Red-winged Blackbirds.
Lastly, Mourning Doves will be much more taupe and tan colored rather than the slate grey of the adults. They are also one of the few birds that are not fully grown when they leave the nest, so a young Mourning Dove will appear just a bit smaller than the adults.
So why all the differences to begin with? Scientists believe it is because the different plumage helps adults identify birds that are not a threat to their territories. If a young bird just looks young, they are less likely to be seen by adults as a territorial intruder may need to be dealt with. This benefits young birds, so they can come and go as they please and not have to defend themselves as rivals.
Young birds only look young for a very short time of the year, so enjoy them while you get the chance. Just like kids of all species, they grow up fast!