Barn owl question...?

Question

Assume an owl eats fifty 1g insects and one 100g rat. In terms of biomass, did the insects or rat contribute the most to the owls diet? How does foraging affect this? Is quality or quantity of prey more important?

If you could help me out with any of these, or give some links to any helpful sites, that would be awesome :]]]

Answer 1

I personally take a lot of interest in such discussions because I am an Environmental Studies major and many of my studies are on this very predicament. Quantity over quality? This all comes down to trophic levels. The further up the trophic level you consume, the more biomass and more carbon energy you acquire to aid in an efficient survival. If an owl consumes 50 , 1g insects that means 50g's of biomass is in its gut. The insect is lower on the trophic pyramid than a rat. When an owl consumes a rat this is contributing greatly to the owls diet and carbon consumption. I think that this question is in constant debate. I personally would say that quality and quantity are equal to each other and should be practiced continuously, one not out ranking the other. I'm sorry if I didn't exactly answer your question, my dear, but I would presume that the answer lies in trophic levels. Good luck with your endeavor and check out the website below:

Answer 2

If you look at owl pellets you will notice when a owl consumes a rat what you have left over is mostly bone and fur. With insects, say a grasshopper, you have exoskeleton mostly. I would guess you have much more exoskeleton in 50 g of grasshoppers than bone and fur in 100g of rat. I know of no way of checking this than by experiment.