We're on day two of closures due to poor weather, but the forecast looks hopeful for tomorrow.
As I sit here with my morning coffee, I thought I'd offer more insight into the swirling vocabulary inside a bird bander's brain with a dive into age class vocabulary.
Local (L): this is a bird, often in the fledgling stage (it just recently left it's nest and is still actively being cared for by adults), that is assumed to have been hatched in the immediate area.
Juvenile (Juv): a bird in juvenile plumage before it's first prebasic molt. The juvenile plumage can be thought of as a bird's first "set" of feathers before it looses (e.g., molts) those feathers and replaces them with another set of feathers (more to come on molt later!). This plumage is generally of lower quality and appears very different than that of an adult; typically this plumage is cryptic and helps these young birds stay camouflaged.
Hatch-year (HY): a bird in it's first-prebasic plumage and in it's first calendar year of life, which means it is less than one year old.
After-hatch-year (AHY): a bird in at least it's second calendar year of age; so an AHY bird is at least 1 year old but it is unknown how much older it could be.
Second-year (SY): a bird in it's second calendar year life (i.e, it is two years old)
After-second-year (ASY): a bird in at least it's third calendar year of age; so an ASY bird is at least 2 years old but it is unknown how much older it could be.
Third-year (TY): a bird in it's third calendar year of life (i.e., it is three years old)
After-third-year (ATY): a bird in at least it's fourth calendar year of age; so an ATY bird is at least 3 years old but it is unknown how much older it could be.
After-fourth-year (A4Y): a bird in at least it's fifth calendar year of age; so an A4Y bird is at least 4 years old but it is unknown how much older it could be.
Fourth-year (4Y): a bird in it's fourth calendar year of life (i.e., it is four years old)
Unknown: a bird of unknown age. Sometimes the physiological evidence that indicates how old a bird is might be conflicting, and it is impossible to know with certainty the age class of bird. We hope that these birds will be captured again so that more information can be collected to determine the age of the bird. We also use this terminology for birds that escape from the mist nets during capture and
Ageing songbirds is fairly simple in someways. With the current techniques and what we know about songbirds right now, we can typically only age songbirds as L, Juv, HY or AHY in the fall (SY or ASY in the spring; make sense? check out the upcoming 'molt' post for the answer). To understand how long songbirds live, means it's essential that we band birds as HY or SY when we have a precise age class to reference when the birds is recaptured or recovered later.
The other age classes (e.g., TY, ATY, 4Y, A4Y) are predominately applicable for woodpeckers and raptors that we capture with less frequency at the station.
Questions? Leave your question in the comments section and I'll respond with an answer!
~Claire
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