Research Article

Effects of Variable Food Supply on the Body Condition of Breeding Tawny Owls Strix aluco in Southern Finland

Table 3

The best generalized linear models showing the relationships between the local food supply and body condition in breeding tawny owls. Other factors probably related to body condition were also included in the preliminary analyses. Estimates, standard errors (SE), test statistics ( 𝑡 ), and their significance ( 𝑃 ) as well as adjusted coefficients of determination for each single variable (Adj 𝑟 2 ) and the difference between adjusted coefficients of determination of subsequent variables in the model ( Δ Adj 𝑅 2 ) are given. For total models, test statistics ( 𝐹 ), their significance ( 𝑃 ), and adjusted coefficients of determination (Adj 𝑅 2 ) are presented.

Variable EstimateSE 𝑡 1 , 1 9 / 𝐹 5 , 1 5 𝑃 Adj 𝑟 2 Δ Adj 𝑅 2

Females
 (Intercept)845.86653.70915.749<.001
 Nestling wing length−1.2080.208−5.819<.0010.3610.361
 Julian Day−2.4730.585−4.224<.0010.1790.107
 Age of bird 25.1048.4782.961.0090.1170.143
 Rats in prey15.229 4.106 3.709.002−0.0520.106
 Shrews in prey−2.2260.853−2.609.0200.0700.075

 Total model16.26<.0010.792

Males
 (Intercept)419.48432.38212.954<.001
 Brood size12.7624.4932.840.0120.4100.410
 Shrews in prey−0.9660.315−3.070.0080.2590.182
 Nestling wing length −0.2340.080−2.941.0100.0410.126
 Age of bird21.4144.5224.735<.0010.3080.116
 Julian Day −0.7940.318−2.496.0250.3890.041

 Total model28.86<.0010.875