Mourning doves are so named because of their sad-sounding coo. They are related to pigeons but have a slimmer build, a gray spot on their heads and a grayish brown hue to their feathers. Mourning dove chicks are sensitive to temperature and will molt (lose and replace their feathers) relevant to the time of year they are born. This means you must consult a calendar before determining a hatchling's age.
A few important definitions to know: 1) Primary feathers are mainly used for flight and located on the outside of the wing. 2) Covert feathers are under the primary feathers to give the wing some height and improve airflow over the top of the wing. 3) Primary covert feathers are directly underneath the primary feathers. 4) Secondary covert feathers are directly underneath the primary covert feathers.
Observe any squabs, or baby doves, still in the nest. A newly born squab will have no feathers. A 4- or 5-day-old squab will begin to develop pin feathers or feathers that look like just the shaft of a regular feather. As squabs develop these feathers, they will have a crossed, mat-like appearance. Older birds that are molting will also have pin feathers. If pin feathers are present, the bird is under 15 days old. These fledgings, squabs with fully developed flight feathers still learning to fly, will stay in the nest for another 20 to 30 days. If a squab with fully developed flight feathers is in the nest, it is between 15 and 45 days old. If a bird with fully developed flight feathers has left the nest, you may identify it by the time of year of its molt.
Look at the primary or outer feathers. The juvenile primary feathers will have a light-colored, smooth margin; the adult primaries will have margins that are frayed and dark colored. A juvenile bird is under 3 years old.
Lift up the primary feather to look at the primary covert. In the case of bird feathers, primary simply means top and second means bottom. The primary feathers, i.e. flight feathers on adults, are simply called primary because they are on the very top. The juvenile primary covert will be fluffy with a tan color. The primary covert feathers will indicate a juvenile regardless of the time of year. If you see at least two white to tan primary covert feathers, go to step 4. If there are no white to tan primary covert feathers, go to step 5.
Watch to see if the last primary feather falls off (drops) before May 7. If the last primary feather drops after May 7, the bird is a hatchling (HY). If the last feather drops before May 7, the bird is a second year (SY).
Check to see if all or most primary/outer feathers have been lost or replaced during the summer/fall molt. If all the primaries have been lost, you will simply see the fluffy covert feathers and no stiffer primary feathers. If they have been replaced, you will see very clean, stiff primary feathers beginning to or completely covering the covert feathers. Any original or older primaries from the past year will be scraggly looking and dirty, mixed with the covert feathers. If original primaries are present, skip to step 6. If no original primaries are present, you may determine the age from the following chart if the summer/fall molt is complete by: - May 15 to August 31: HY - September 1 to May 31: Unknown Age - January 1st to May 14th: Adult Mourning Dove (AHY) (Official birding symbols for bird ages)
Observe the birds continuously until May 7. If the last primary is lost before May 7, it is a SY. If the last primary is lost after May 7, the bird is still in its HY.