Pesticide risk assessment for birds and mammals
Blue tit Cyanistes caeruleus
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- Country Population size
- Agricultural association
- (bold)
- 90 percentile Reference All birds
- Body weight
- Risk assessment
5.1.12Blue tit Cyanistes caeruleusGeneral information The blue tit is widespread and common throughout the Zone south of the July isotherm of 14°C (Snow & Perrins 1998). Its primary habitat is deciduous woodland but it also occurs in coppice, overgrown marshes and mires etc. The species is frequent in parks, gardens and other man-made habitats, provided suitable nest-holes are available. Blue tits are resident in the southern part of the Zone while birds from northern populations are partial migrants. Northern birds make irregular eruptive movements, mainly towards south-west (Snow & Perrins 1998). Populations may be somewhat fluctuating, perhaps related to winter temperatures, but overall numbers have probably increased during recent decades (Table 5.). Table 5.. Population size and trends of blue tit (breeding population) in the Nordic and Baltic countries. Sources: BirdLife International/European Bird Census Council (2000), BirdLife International (2004), Ottosson et al. (2012).
Over much of central and northern Europe egg-laying begins mostly in the last week of April and the first few days of May (Snow & Perrins 1998), maybe a little later further north. Median laying date is 7 May in South-west Sweden and South Finland (Cramp & Perrins 1993, Glutz von Blotzheim & Bauer 1993). Blue tits are usually single-brooded, but in some populations 10 to 50 % of the breeding pairs may produce a 2nd clutch in some years (Cramp & Perrins 1993, Glutz von Blotzheim & Bauer 1993). Clutch size (mostly 10-12, occasionally 16-18) is the largest among European passerines. Agricultural association Blue tits are fairly common in rural gardens, deciduous hedgerows and habitat islands, but the species is not considered relevant for field crops due to its habitat preferences of broad-leaved forest, parks and gardens (Svensson et al. 1999, Larsen & Heldbjerg 2009). The habitat preferences include orchards and nurseries, provided suitable nest-holes are available. In a study of orchards in the UK, 20 blue tits were radio-tracked to estimate the active time spent in this habitat (Crocker et al. 1998, Finch & Payne 2006, Prosser 2010). The results are summarized in Table 5.. Table 5.. Percentage of active time spent by radio-tagged blue tits in orchards in the UK, presented as 90th percentile of the modelled PT distribution. The birds were caught inside the orchard or along the orchard edge; it is therefore recommended to use the values for the total sample of tracked birds (bold).
Body weight Body weight of both sexes mostly 9.5 – 12.5 g (Snow & Perrins 1998). Mean body weight (11 g) may be used for risk assessment. Energy expenditure No species specific data available, therefore calculated allometrically using the equation for passerine birds in accordance with the formula in Appendix G of the EFSA Guidance Document (EFSA 2009). Diet Blue tits are mostly foraging in the foliage of trees and bushes (Cramp and Perrins 1993). Ground-feeding occurs mainly in winter, when searching for beech mast etc. In an English study, the percentage of feeding observations on the ground was as follows: January-February 10-15, March 4, April 2, May-August 0, September-October 1, November 5, December 7 (Gibb 1954 cited in Cramp & Perrins 1993). The diet of blue tits is reflecting seasonal changes with more seeds and fruits in winter and almost exclusively invertebrates in the breeding season (Cramp and Perrins 1993). In SW England, nuts and seeds from trees (beech, oak, chestnut, birch) were found in 13 % of blue tit gizzards in September, 59 % in October, 44 % in November, 40 % in December, 31 % in January, 7 % in February and 0 % in March-August (Betts 1955 cited in Cramp & Perrins 1993). More detailed, quantitative data on diet composition are apparently not available, but invertebrates almost certainly make up the bulk of the diet throughout the year. The nestling diet consists of invertebrates (Cowie and Hinsley 1988). Risk assessment The blue tit is relevant for the following scenarios:
During March - September, the diet may be assumed to consist entirely of foliage arthropods (PD = 1). Outside this period, nuts and seeds from trees enter the diet but probably never make up more than 50 %; this part of the diet shall be regarded as unsprayed. For applications in (March) April - September, PT may be refined using the information in Table 5.. Directory: media media -> Applications to Drill media -> Unicef voices of Youth Chat Theme: Children and aids nigeria and Zimbabwe 13 October 2006 Background media -> Tsunami Terror Alert: Voices of Youth media -> Biblical Eschatology Presentation by: D. Paul Beck May 4, 2016 Ground Rules media -> Guide to completing the collection using the Omnibus system media -> The milk carton kids media -> Events Date and Location media -> The Gilded Age: The First Generation of Historians by H. Wayne Morgan University of Oklahoma, April 18, 1997 media -> Analysis of Law in the United Kingdom pertaining to Cross-Border Disaster Relief Prepared by: For the 30 June 2010 Foreword media -> Cuba fieldcourse 2010 Download 2.61 Mb. Share with your friends:
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