Food consumption, energy, nutrient and mineral balances in a eurasian kestrel and a screech owl

Abstract

1. 1. The food consumption, energy, nitrogen, fat, ash, calcium, phosphate and magnesium balances of the Eurasian kestrel ( Falco tinnunculus), and screech owl ( Otus kennicotti) are compared. 2. 2. Eurasian kestrel sample values were significantly greater than screech owl sample values in the energy, nitrogen, calcium, phosphate and magnesium content in pellets, and calcium content in excrement. Phosphate content in excrement was significantly greater in screech owl samples than in Eurasian kestrel samples. 3. 3. The Eurasian kestrel ingested significantly greater amounts of calcium and phosphate, egested via excrement significantly greater amounts of ash, excreted or egested significantly greater amounts of energy, nitrogen, calcium and phosphate via excrement and pellets, and excreted significantly greater amounts of magnesium via excrement than did the screech owl. The screech owl assimilated significantly greater amounts of ash than did the Eurasian kestrel. 4. 4. The metabolizability coefficient averaged 48.32% for the Eurasian kestrel, and 49.62% for the screech owl.