with Peter Nye's Observations
"I was thinking about the 2 birds we trapped today, and the weather," wrote eagle biologist Peter
Nye. "Good study question for students: See if you can come up with a reason why eagles might have been 'feeding
up' on 1 February. I have some opinions on this from years of trapping, but it certainly could be more scientifically
investigated and described!
- What weather systems did we have leading up to capture day, and what was expected later that day--or on 2 February?"
"Over the years I've been watching & trapping eagles, there seem to be a couple of distinct times when
eagles really 'feed up':
- When they sense a change in barometric pressure, especially a low pressure system approaching. (And I think
they can/do sense this!) Low pressure usually means poor weather and/or a storm is approaching. Eagles have no
clue how long lousy weather might last, or how severe. So, it's smart to "store up" ahead of it. (Look
at the weather chart and maps below and see how the
pressure dropped before capture on February 1st. Also note the cloud cover and storm that did follow.)
I think it is a pressure-sensitive thing, but a 2nd possibility:
- After a stretch of prolonged poor weather, esp. when it has been very cold and everything (ie carrion) frozen.
When we get a warm-up day, with higher temps (like maybe near 30, sunny) that items like deer carcasses once again
possible (or more attractive) to feed on.
Of the two though, the first is more reliable, assuming eagles can identify/predict those days. I must state
this is conjecture on my part; never have seen any scientific exploration on the subject. (Maybe something Journey
North students could do!)"
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