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

S2Summary of food supplementation studies of blue (BT) and great (GT) tits. The bottom row summarizes the findings of Robb et al. (2008a), the most recent review of supplementation studies across multiple species of birds (number of studies cited is given). Comparisons are between supplemented and non-supplemented (control) birds unless stated otherwise. Clutch initiation date: ‘+’ later, ‘-’ earlier; clutch size: ‘+’ larger, ‘-’ smaller; incubation period: ‘+’ longer, ‘-’ shorter; hatching success: ‘+’ higher, ‘-’ lower. Non-significant effects are denoted by ‘N.S.’. Empty cells represent non-published variables. ‘N/A’ not applicable (e.g. because of the timing of supplementation).

Sp. / Food supplement(s) / Clutch initiation date / Clutch size / Incubation period / Hatching success / Brood size / Reference
BT / Mealworms / N/A / N/A / - / + / Nilsson and Smith (1988)
BT / Sunflower seeds, margarine, dried insects, mealworms, and tineas / - / N.S. / N.S. / Clamens and Isenmann (1989)
BT / Mealworms / - / N.S. / Nilsson and Svensson (1993)
BT / Mealworms / - / N.S. / N.S. / N.S. / N.S. / Nilsson (1994)
BT / (i) Mealworms; (ii) Mealworms and boiled chicken egg / - / N.S. / Svensson and Nilsson (1995)
BT / (i) Lard; (ii) boiled chicken egg, lard and oatmeal / - / N.S. / N.S. / N.S. / Ramsay and Houston (1997)
BT / (i) Peanuts enriched with essential amino acids a; (ii) peanuts not enriched with essential amino acids b. / N.S. / + a vs. b or control
N.S.b vs. control / N.S. / N.S. / N.S. / Ramsay and Houston (1998)
BT / Peanuts / - / N.S. / Robb et al. (2008b)
GT / Mealworms / - / Källander (1974)
GT / Sunflower seeds, margarine, dried insects, mealworms, and tineas / N.S. / N.S. / N.S. / Clamens and Isenmann (1989)
GT / (i) Sunflower seeds in coconut fat; (ii) mealworms in coconut fat / - / + / N.S. / N.S. / Nager et al. (1997)
Review of supplementation studies of birds / - = 34
+ = 1
N.S. = 24
Total = 59 / - = 1
+ = 28
N.S. = 34
Total = 63 / - = 2
+ = 0
N.S. = 7
Total = 9 / - = 0
+ = 9
N.S. = 11
Total = 20 / Robb et al. (2008a)

References

Clamens A, Isenmann P (1989) Effect of supplemental food on the breeding of blue and great tits in Mediterranean habitats. Ornis Scand 20:36–42

Källander H(1974) Advancement of laying of great tits by the provision of food. Ibis 116:365–367

Nager RG, Rüegger C, van Noordwijk AJ (1997) Nutrient or energy limitation on egg formation: a feeding experiment in great tits. J Anim Ecol 66:495–507

Nilsson JÅ (1994) Energetic bottle-necks during breeding and the reproductive cost of being too early. J Anim Ecol 63:200–208

Nilsson JÅ, Smith HG (1988) Incubation feeding as a male tactic for early hatching. Anim Behav 36:641–647

Nilsson JÅ, Svensson E (1993) Energy constraints and ultimate decisions during egg-laying in the blue tit. Ecology 74:244–251

Ramsay SL, HoustonDC (1997) Nutritional constraints on egg production in the blue tit: a supplementary feeding study. J Anim Ecol 66:649–657

Ramsay SL, HoustonDC (1998) The effect of dietary amino acid composition on egg production in blue tits. Proc R Soc Lond B 265:1401–1405

Robb GN, McDonald RA, ChamberlainDE, Bearhop S (2008a) Food for thought: supplementary feeding as a driver of ecological change in avian populations. Front Ecol Environ 6:476–484

Robb GN, McDonald RA, Chamberlain DE, Reynolds SJ, Harrison TJE, Bearhop S (2008b) Winter feeding of birds increases productivity in the subsequent breeding season. Biol Lett 4:220–223

Svensson E, Nilsson JÅ (1995) Food supply, territory quality, and reproductive timing in the blue tit (Parus caeruleus). Ecology 76:1804–1812

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