From hatching until December 31st of that calendar year, these SSHA are considered hatch year (HY). The subsequent year they are considered second year (SY), and so on. Simple enough. But, these birds don't molt on December 31st and January 1st, so the different plumage types don't correlate exactly with their calendar age. These birds generally molt in the fall; therefore, a SY SSHA early in the year (before molt) looks different than a SY SSHA late in the year (after molt). Also, SSHA that are past their 3rd calendar year don't show enough unique characteristics to age any farther than third year (TY) in December or after third year (ATY) in January. So, even if a SSHA is in its 5th calendar year, it would still be called an ATY.
So, to avoid confusion I will call our three Sharp-shinned Hawks juvenile, sub-adult, and adult. The juvenile hatched in 2011 and was a HY in December but a SY now, the sub-adult hatched in 2010 and just became an third year (TY) bird, and the adult hatched in 2009 or earlier and is now considered an after third year (ATY).
Now we will compare our two new SSHA to the one from last month in the post Birds in Hand: A Couple of Recent Favorites.
|This is how we weigh birds. There is no harm done by putting the bird in a can or cup. [Photo by Luke Musher]|
|Here is a juvenile male Sharp-shinned Hawk. Note the yellow iris and thick, brown streaking (running the length of|
the body) as these are characteristic of juvenile SSHA. [Photo by Luke Musher]
|Another look at the juvenile male Sharp-shinned Hawk. [Photo by Luke Musher]|
|A closer look at the sub-adult SSHA (SY last week, ASY today). Again, note the orange iris and rufous barring. [Photo|
by Cory Ritter]
|Here is another look at the AHY male Anna's Hummingbird. [Photo by Dan Lipp]|
|Cory measuring the wing-chord of a Bewick's Wren. [Photo by Dan Lipp]|
|Bewick's Wren posing for the camera. [Photo by Dan Lipp]|
|Posing, once more. [Photo by Dan Lipp]|
|SY/TY Red-breasted Sapsucker [Photo by Cory Ritter]|
By Cory Ritter and Luke Musher