RE- SEA EAGLE CATCHING SEAGULL IN MID AIR

[Andrew Taylor <>]

On Tue, Jun 26, 2012 at 04:02:10PM +1000, Stephen Ambrose wrote:
> Therefore, there is a risk of the WBSE using up too much energy to
> capture a gull in comparison with the energy it would gain from consuming
> one (if it is lucky enough to capture a gull).

I was curious enough to do back-of-the-envelope calculations from
detailed estimates I found for Bald Eagles.

Wintering Bald Eagles require about 2000kJ of food/day.

With smaller size and warmer climate that might be 1500kJ of food/day
for a WBSE.

A silver gull might weigh 350g, which might equate to 2500kJ.

So 1 Silver Gull day looks to be enough for a WBSE.

Bald Eagles are estimated to use ~10kJ/minute in flapping flight and
~3kJ/minute when soaring/gliding.  Active pursuit must burn more energy,
but it looks like an WBSE could easily afford to spend more then  an
hour pursuing each gull caught.

Andrew