Migration
Mystery: Timing
Sara Zimorski, ICF
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"Some
things about these birds are a mystery — and will probably
always remain a mystery!" |
March
2009
Even though many older cranes have started or even completed spring
migration, we don’t expect the ultralight juveniles to leave as early
as the older birds. Every year the ultralight birds at Chassahowitzka have
left
within a two-week
span (last week of March, first week of April) — regardless of when
they arrive in Florida or how long or short their stay at the winter pen.
The timing of their departure from Chass seems to be tied in to when the wild flock of whoopers normally leave Aransas. Now we expect this will be true of the juveniles wintering at St. Marks NWR, but we don’t know for sure. We will certainly be watching them, very curious to find out when they leave!
In future years these birds will be older and leave Florida earlier. Some of them will leave early with sandhills. Others will leave earlier to get back to their established territories at Necedah NWR, the summer nesting grounds.
Something I don’t fully understand: why don't the younger, unpaired, non-breeding birds wait longer before heading back? Some things about these birds are a mystery — and will probably always remain a mystery!
Journal or Discussion Questions
-
What do YOU think might explain the connection between timing for the naturally wild flock at Aransas and the juveniles wintering in Florida?
- Sara is a scientist, but she thinks some things about cranes may always remain a mystery. What is one thing in life for which you wish we had answers?
