Electronic Supplementary Material to Does Food Supplementation Really Enhance Productivity

Electronic supplementary material to ‘Does food supplementation really enhance productivity of breeding birds?’ by Timothy J. E. Harrison, Jennifer A. Smith, Graham R. Martin, Dan E. Chamberlain, Stuart Bearhop, Gillian N. Robb, and S. James Reynolds

S1 Models of reproductive parameters (F and associated P values) in blue (BT) and great (GT) tits at Chaddesley Woods National Nature Reserve in 2006 to 2008. Combined-year analyses except BT and GT incubation period (significant year × treatment interactions, P ≤ 0.05). Fixed factors specified in each model are given with significant P values in bold text. Directions of significant effects are given: ‘-’ a significant negative association and ‘N.S.’ non-significance (P > 0.05). Dietary treatment effects are illustrated in Figs 1–3. See main text for details.

Breeding parameter Sp. Year Fixed factor F P Direction

Clutch initiation date BT 2006-08 Dietary treatment F1,187 = 11.06 P = 0.001 Year F2,187 = 101.16 P < 0.001 2006: latest; 2007: earliest. GT 2006-08 Dietary treatment F1,86 = 22.51 P < 0.001 Year F2,86 = 54.89 P < 0.001 2006: latest; 2007: earliest.

Clutch size BT 2006-08 Dietary treatment F1,151 = 7.65 P = 0.006 Year F2,151 = 82.81 P < 0.001 2006: largest; 2007: smallest. Clutch initiation date F1,151 = 141.66 P < 0.001 - GT 2006-08 Dietary treatment F1,81 = 10.10 P = 0.002 Year F2,81 = 15.14 P < 0.001 2006: largest; 2008: smallest. Clutch initiation date F1,81 = 16.29 P < 0.001 -

Incubation period BT 2006 Dietary treatment F1,125 = 9.44 P = 0.003 Clutch completion date F1,125 = 22.70 P < 0.001 - Clutch size F1,125 = 7.64 P = 0.007 - 2007 Dietary treatment F1,139 = 0.32 P = 0.57 Clutch completion date F1,139 = 19.86 P < 0.001 - Clutch size F1,139 = 30.85 P < 0.001 - 2008 Dietary treatment F1,98 = 17.98 P < 0.001 Clutch completion date F1,98 = 110.54 P < 0.001 - Clutch size F1,98 = 0.00 P = 0.95 N.S. Clutch completion date × F1,98 = 11.05 P = 0.001 Supplemented: seasonal shortening less dietary treatment pronounced than in the control.

GT 2006 Dietary treatment F1,60 = 30.05 P < 0.001 Clutch completion date F1,60 = 0.45 P = 0.50 N.S. Clutch size F1,60 = 0.22 P = 0.64 N.S. Clutch completion date × F1,60 = 4.40 P = 0.04 Supplemented: seasonal lengthening; dietary treatment control: seasonal shortening. Clutch size × dietary F1,60 = 11.20 P = 0.001 Supplemented: longer with larger clutches; treatment control: the opposite. 2007 Dietary treatment F1,71 = 6.88 P = 0.01 Clutch completion date F1,71 = 13.69 P < 0.001 -

1 Clutch size F1,71 = 15.80 P < 0.001 - 2008 Dietary treatment F1,100 = 4.32 P = 0.04 Clutch completion date F1,100 = 58.27 P < 0.001 - Clutch size F1,100 = 7.65 P = 0.007 -

Hatching success BT 2006-08 Dietary treatment F1,132 = 8.10 P = 0.005 Year F2,132 = 1.02 P = 0.36 N.S. Hatch date F1,132 = 0.26 P = 0.61 N.S. Hatch date × dietary F1,132 = 6.65 P = 0.01 Supplemented: seasonal increase; control: treatment seasonal decrease. GT 2006-08 Dietary treatment F1,71 = 0.22 P = 0.64 Year F2,71 = 7.41 P = 0.001 2006: highest; 2008: lowest. Hatch date F1,71 = 0.01 P = 0.91 N.S.

Brood size BT 2006-08 Dietary treatment F1,129 = 8.28 P = 0.005 Year F2,129 = 23.46 P < 0.001 2006: largest; 2007: smallest.

Hatch date F1,129 = 19.34 P < 0.001 -

GT 2006-08 Dietary treatment F1,69 = 5.51 P = 0.02

Year F2,69 = 2.89 P = 0.06 N.S.

Hatch date F1,69 = 0.01 P = 0.93 N.S.

Hatch date × dietary F1,69 = 4.42 P = 0.04 Supplemented: seasonal increase; control: treatment seasonal decrease.