[CT Birds] What Birders do on a snowy morning...

Arthur Shippee ashippee at snet.net
Thu Dec 27 11:33:34 EST 2012

But there are other factors. Dove may expend more energy per unit seed in digestion, and so need to eat more to gain unit energy. Dove expends more in flying, &c., and needs to eat more. Both would raise the time at feeder and in danger. Also, dove is a bigger target, and slower acceleration. The whole system is complicated!  

Tx for data and idea!

Sent from my iPhone

On Dec 27, 2012, at 10:46 AM, Carrier Graphics <carriergraphics at sbcglobal.net> wrote:

> What Birders do on a snowy morning...
> I look out at the 6 new inches of snow, and find the birds
> are all over the feeders. On my window screen feeder are 3 Mourning Dove, and 
> 4 Junco. I notice how the Doves seem to be eating many more seeds per second
> that the juncos. I know this happens because all those in the Dove and Pigeon 
> Family
> do not need to crack open seeds, just eat them whole, and let their crop do the 
> cracking/digestion.
> So: I count how many seeds are picked up per minute for each species, then 
> average out the short periods of time they are not picking up seeds per min. Ex- 
> walking over to a new seed area, head lifting for danger, etc. And here is what 
> I came up with...
> On average, a Dove picked up 5 seeds per second X 60 = 300 seeds per minute.
> minus 6 intervals of 2 sec each = 12 seconds, 12 X 5= 60 seeds
> So 300 seeds per minute, minus 60 seeds less for intervals = 
> The MOURNING DOVE eats 240 seeds per minute!
> On average, a Junco picks up 1 seed and cracks it open and swallows 
> it at one per second X60 = 60 seeds per minute.
> The Junco takes 10 intervals of 2 seconds each = 2 X 10 = 20 seconds = 20 seeds.
> So 60 seeds per minute, minus 20 seeds less for intervals =
> The JUNCO eats 40 seeds per minute.
> Conclusion:
> The efficient DOVE eats 200 more seeds per minute. And this gives this much 
> larger bird a less chance of being taken by a predator from less time spent in 
> the open finding food than a JUNCO, because they do not need to crack open each 
> seed at the site of the food, but can digest them from the safety of a tree or 
> such that affords them safety from a predator. Yes?
> Paul Carrier - Harwinton
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