Western Osprey (Pandion haliaetus) Science Article 1
A female Osprey (Pandion haliaetus) usually is fed exclusively by its mate between pair formation and egg-laying. Laying dates and courtship periods, but not clutch size, egg size, breeding success or female weight reserves, were correlated (negatively) with the prelaying feeding rates of 12 females breeding in a coastal Massachusetts colony. However, the age of a pair and of its bond influenced laying dates and courtship periods more than food intake. Older and more experienced pairs arrived earlier and laid eggs more quickly than younger pairs.
ALAN POOLE, The Auk 102: 479-492