Contents of report
Breeding Bird Survey
Common Birds Census
Constant Effort Sites
Nest Record Scheme
Waterways Bird Survey
Alerts
Summary
What the categories mean
Return to BTO Home Page
.
RED-THROATED DIVER Gavia stellata
 
Conservation Listings Long term trend

Table 4/Amber (European status)
Biodiversity Steering Group
Conservation Concern List

UK: Unknown
Shetland: Stable

 
Status Summary
Increasing nest failure rates during the egg stage is worrying for this species because of its unfavourable European conservation status. The increase represents a change from 13% to 42% of nests failing over the 27-day egg stage (26d incubation + 1d egg laying). It should be noted that, although many of the nest records come from Orkney, there are reasonable numbers of records also from Shetland, mainland Scotland and Western Isles. Population trends are not monitored by the BTO, but the UK Seabird Monitoring Programme shows that numbers on Shetland have fluctuated around a stable level between 1980-99 (Upton et al. 2000).
 
Annual breeding population changes are not currently monitored by BTO for this species
Table of productivity information for Red-throated Diver
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 18 1980-1998 29 None       Small sample
Brood size 18 1980-1998 42 Linear increase 1.25 chicks 1.44 chicks 0.19 chicks  
Daily failure rate (eggs) 18 1980-1998 17 Linear increase 0.005 nests/day 0.0199 nests/day 0.0149 nests/day Small sample
Daily failure rate (chicks) 18 1980-1998 22 None       Small sample
 

 

Insufficient data on laying date
available for this species

 

 

Insufficient data on CES
available for this species

 

   



The report should be cited as: Baillie, S.R., Crick, H.Q.P., Balmer, D.E., Bashford, R.I., Beaven, L.P., Freeman, S.N., Marchant, J.H., Noble, D.G., Raven, M.J., Siriwardena, G.M., Thewlis, R. and Wernham, C.V. (2001) Breeding Birds in the Wider Countryside: their conservation status 2000. BTO Research Report No. 252. BTO, Thetford. (http://www.bto.org/birdtrends)

[ Welcome | Contents | Introduction | CBC | WBS | BBS | Heronries | CES | NRS | Alerts ]
[ Summary | Discussion | References | Help | BTO Home Page ]

© British Trust for Ornithology
BTO, The Nunnery, Thetford, Norfolk IP24 2PU
Tel: (+44) (0) 1842 750050 Fax: (+44) (0) 1842 750030 Email:

Last updated: Last updated: 9 April, 2001

Page created by Susan Waghorn