Reed Warbler in County Durham
History
There are three isolated historic breeding records –
1830 Between Blaydon and Derwenthaugh (Tetrad NZ16W) Nest with eggs.
1885 Near Ravensworth (Tetrad NZ25J or adjacent). Nest with four eggs.
1894 Near Hell Kettles (Tetrad NZ21V – NZ2810). Nest.
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A colony was established in Gosforth Park, Northumberland, around 1958 and is believed still to be thriving. Parslow (1967) in British birds vol 60 noted that the species bred in every English county except Durham, but only occasionally in Cumberland and at single localities in Westmorland and Northumberland.
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A slow start
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Around the late 1960, also, Reed Warblers began to turn up as occasional passage migrants on the Durham coast, usually in autumn.​
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The colonisation of the historic County Durham is documented in some detail in The Birds of Durham (Bowey and Newsome, 2012). This covers the breeding seasons up to 2010 but does not fully include the data submitted to the national Bird Atlas, 2007-2011 (see below). It is the source for most of this summary
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Suspected breeding occurs at many sites a year or two before breeding is confirmed, so the chronology of the next few years is
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​1969 Billingham Bottoms (Tetrad NZ42K/NZ42L). Birds seen in May.
1970 Billingham Bottoms (Tetrad NZ42K/NZ42L). Birds seen in August.
1970 The Durham County bird report for 1973 recorded a report that single pairs had bred at a locality in Weardale “for the past three years” [i.e. 1970 to 1972?] and had been present in 1973, when the outcome was unknown. The site is now known to be Low Butterby (Tetrad NZ23U) and this is the first record of breeding in the historic County Durham in the 20th century.
1972 Haverton Hole (Tetrad NZ42W). Male singing in June. This site is now part of RSPB Saltholme.
1973 Haverton Hole. Two Spring birds.
1973 Low Barns (Tetrad NZ13K/NZ13Q). Bird singing in June.
1974 Haverton Hole. Juvenile mist-netted in August.
1975 Haverton Hole. Breeding suspected; one or two birds in song from 8 June, a pair held territory into July and reports continued into September.
1976 Haverton Hole. Four to five birds held territory; breeding proved; ten adults ringed between late June and early August.
1979 Wildfowl and Wetlands Trust site, Washington (Tetrad NZ35H/35I). A reedbed was established here during the late 1970s and a bird sang from 15 June to 17 July 1979.
Shibdon Pond (Tetrad NZ16W – NZ1962). Single bird ringed in August.
1980 Shibdon Pond. Single bird ringed in May.
1981 Wildfowl and Wetlands Trust site. One individual summered.
1982 Haverton Hole. Estimated ten pairs and around this time new sites began to be established up and down River Tees
1982 Wildfowl and Wetlands Trust site. Three birds present.
1982 Shibdon Pond. One singing.
1983 Wildfowl and Wetlands Trust site. At least three pairs breeding annually from this date.
1983 Shibdon Pond. Two to three birds present from 5 June to 30 August.
1985 Wingate (Tetrad NZ43D). Two singing birds on 10 May.
1986 Shibdon Pond. Breeding confirmed.
Wingate. One bird present on 1 June.
1987 Shibdon Pond. Breeding confirmed.
1991 Shibdon Pond. Breeding confirmed.
1992 Shibdon Pond. Breeding confirmed. Four males appeared to be in territory.
1993 Shibdon Pond. Up to six territories.
1995 Low Butterby. More than ten singing birds.
1996 Low Butterby. Three to four birds singing on 13 June following reduction in the area of the reedbed since the previous breeding season.
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​Colonisation and Growth​
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Meanwhile, on the North Tees Marshes, expansion of the population proceeded at some pace. Blick, M. A. (2009): Birds of Cleveland (quoted in Bowey and Newsome, 2012) reported survey data –
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1987 27 singing birds at eight localities
1997 About 40 pairs at 10 localities
2004 At least 60 pairs
2007 About 200 pairs
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At the same time the fieldwork for the 2000 to 2006 atlas The breeding birds of Cleveland (Joynt, G.J., Parker, E.C. and Fairbrother, V., 2008) estimated approximately 400 pairs across Teesmouth.
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Ringing data from the North Tees Marshes also illustrates the growth in numbers
2006 Dorman’s Pool (North Tees Marshes) (Tetrad NZ52B). 48 adults and 118 juveniles ringed.
2006 Saltholme. 94 adults and 147 juveniles ringed (probably including Haverton Hole).
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​Northward Expansion
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By 2007 “breeding was strongly suspected at six Durham sites away from Teesmouth as well as the established breeding birds at Shibdon Pond and WWT Washington”. [For this year the distinction is clear; for some other years Teesmouth and the rest of Durham appeared to be linked together in a single estimate.]
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The spread of the species is dependent on suitable habitat. More such habitat is being created and seems often to be colonized quite quickly.
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A summer atlas of the breeding birds of County Durham (Westerberg, S. and Bowey, K., 2000) was based on the fieldwork for B.T.O. New atlas of breeding birds in Britain and Ireland, 1988-1991, but supplemented by some local “gap-filling” fieldwork during 1992 and 1993. It concluded that “The Durham population appears to be in the region of 120 pairs at present, of which about 100 are on the Tees Marshes.” It showed 12 occupied tetrads.
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As noted above, Bowey and Newsome, 2012 does not fully include the data submitted to the national Bird Atlas, 2007 – 2011, but the distribution they represent, together with additional Durham Bird Club data for the breeding season (April to July) in 2008 to 2012, is shown in the map.
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This shows a total of 49 tetrads, though five of the 12 tetrads shown as occupied in 1988 to 1993 do not figure in the data for 2007 to 2012.
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These are breeding season records and – as mapped – do not distinguish “possible”, “probable” and confirmed” breeding, though autumn coastal passage is excluded by the limitation to the months of April to July.
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Selected ringing data for about a dozen birds is included in Bowey and Newsome 2012. These mainly relate to movements to and from the North Tees Marshes. Other sites are
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Ringed Staffordshire Summer 1981
Recovered Shibdon Pond Summer 1982
Ringed Shotton, Clwyd, Wales September 1990
Recovered Shibdon Pond Spring 1993 Breeding male
Ringed Saltholme May 2008 Adult female
Controlled Hondaribbia, Guipuzcoa, Spain August 2008
Re-trapped Rainton Meadows (Tetrad NZ34J) 14 May 2009
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