Study

Effects of provision of supplementary calcium on pied flycatchers Ficedula hypoleuca and great tits Parus major breeding in calcium-poor and calcium-rich habitats around Kilingi-Nõmme, Pärnu, Estonia

  • Published source details Tilgar V., Mänd R. & Leivits A. (1999) Effect of calcium availability and habitat quality on reproduction in pied flycatcher Ficedula hypoleuca and great tit Parus major. Journal of Avian Biology (formerly Ornis Scandinavica 1970-1993), 30, 383-391

Actions

This study is summarised as evidence for the following.

Action Category

Provide calcium supplements to increase survival or reproductive success

Action Link
Bird Conservation

Provide calcium supplements to increase survival or reproductive success

Action Link
Bird Conservation
  1. Provide calcium supplements to increase survival or reproductive success

    A replicated, controlled trial in deciduous forests in Estonia in 1995-6 (Tilgar et al.1999) found that pied flycatchers Ficedula hypoleuca and great tits Parus major used supplementary calcium supplied to their nest boxes, and that, in base-poor habitats, supplemented flycatchers laid larger eggs with thicker shells, compared to controls. There was no difference in tits, or in either species for hatching success or nestling condition. This study used a subset of data from studies described in detail below.

     

  2. Provide calcium supplements to increase survival or reproductive success

    A replicated, controlled study in a 30 km2 area of base-poor pine forests in Estonia in 1995-7 (Tilgar et al. 1999) found that great tits Parus major provided with supplementary calcium began laying earlier and had larger clutches than controls (average first laying date of 27th April-6th May for 42 supplemented nests and average clutch volume of 17.6 ml for 36 clutches vs. 29th April-11th May, 84 clutches and 16.6-18.4 ml, 65 clutches). In addition chicks from supplemented nests were larger than controls in 1997, the worst year for reproduction. There were no differences between groups with respect to clutch size (10.6-11.5 eggs/clutch, 40 supplemented clutches vs. 10.3-11.2 eggs/clutch for 81 controls), the size of individual eggs, hatching success or the number of fledglings produced (92-7% success and 7.8-8.9 fledglings/clutch for 29 supplemented clutches vs. 93-5% and 7.0-8.6 fledglings/clutch for 48 controls). Supplementary calcium consisted of snail shell and chicken eggshell supplied constantly in small feeders on the outside of nestboxes, from approximately 2 weeks before the start of nesting. This study uses a subset of the data from Tilgar et al. 2002.

     

Output references

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