On the east bank of the river Medway,between Wouldham and Aylesford,there are areas of hawthorn and willow scrub.Some of these areas were former cement and brick works,which closed in the first half of this century.When I first visited the Eccles site in the early 1960`s,two-three pairs of Wrynecks Jynx torquilla were still breeding and both Whinchat Saxicola and Red-backed Shrike Lanius collurio nested there in 1965.I also regularly recorded up to ten singing Nightingales Luscinia megarhynchos.
Apart from the building of a water treatment works in the 1970`s and the removal of small areas of scrub in a cleaning up operation in the 1980`s,the area remains much the same.Nightingales still breed in the remaining scrub in much the same numbers,while on the west bank of the Medway,in the New Hythe and Leybourne lakes area,they have been spreading in increasing numbers,since the early 1980`s and there were ten pairs there in 1991.Four pairs also breed on the west bank at Holborough marshes,while a few scattered pairs nest along the Downs,above Burham,where I heard three singing in both 1970 and 1980.The total population in all these areas is between 45-50 pairs.
The best of these scrubland areas,along both banks area now protected by statutory,or non-statutory designations,as Sites of Nature Conservation interest,but this does not guarantee their safety from one kind of development or another.An area known as the Island Site has,since the late 1970`s,had the highest density of breeding Nightinglaes in the area,and maybe in Britain.If,however,the proposed new river crossing is built,it could cut straight through the Island Site.
The Island Site
The Island Site,not to be confused with Eccles Island,which borders it to the north,was formerly a marsh.In the 1960`s the owners,Reed International,dumped paper pulp into the area.This then dried and settled,forming a crust some 300-450 mm thick.Willow carr,nettles,buddleia,silver birch,bramble and bracken then slowly took over.The northern area has a pond and,before the drought of recent years,most of it was damp.The southern part is drier,with more bracken,buddleia and elder,while the western boundary is the original river bank,with willow,oak and more elder.Along the eastern boundary there is a paper storage area.
In 1979.when it was realised that a high density of Nightingales was breeding in a relatively small and easily accessible area,a bird-ringing study was commenced.Birds trapped using mist nets (no pulli were ringed),were sexed,aged,weighed and measured.In particular ,the flattened ,straightened wing length (maximum chord) was very carefully recorded.Apart from the net site where each bird was trapped,only general notes were taken.It was considered that a more detailed study would be too time consuming.
Ringing commenced each spring,around 20th April,and was continued until the end of June on a once a week basis,from dawn until 10.00 a.m.Netting between july and September was much less frequent.By July the adults start their moult.They become very skulking and difficult to catch,while the vegetation becomes so tall that it inhibits ringing.
Map 1.Location of breeding Nightingales in the Burham/Eccles area 1991.Key to Map.A total of 40 pairs bred in 1991,plotted on the map as follows.
Horizontal hatching = Part of Island Site (including Ringing area) with densest population (11 pairs in 1991)Diagonal hatching = Remainder of Island Site (nine pairs in1991).Vertical hatching = Eccles old factory area (10 pairs in 1991).Filled dots = Individual singing males (10 pairs in 1991).recorded on the west bank of the Medway.
Between 1979-1992 a total of 1,739 birds of 42 species were ringed and of these just over 6% were Nightingales.The earliest date for Nightingales at this site is 4th April.By the end of the second week, they are usually back in some numbers.The only exception to this was in 1992,when the first bird was not heard until 18th April,but the breeding numbers were also down to just six pairs that year,from 11 pairs in 1991.Males arrive first and sing from quite exposed perches,but after breeding commences,they become far less visible.It is given throughout April and May but by early June it is far less frequent.The latest song noted was on 3rd July 1982,albeit only a short burst.
The most sort after territories are in willow carr,followed by bramble and then buddleia,nearly all of which have an undergrowth of nettles,with a good leaf litter.The only exception is in the southern area where two-three pairs breed in a mixture of buddleia and bracken.In the most sort after sites,males have been singing only 20 metres apart.
By the second week in May,the females have a well developed brood patch,but the first juveniles are not trapped in the nets until the third week in June.A full moult of the adults commences at the beginning of July and takes about 45 days to complete,juveniles only have a partial moult.During this period,the species is very secretive,spending a lot of time on or near to the ground,their presence only given away by a churring,scolding note from deep in the undergrowth.They leave for their African winter quarters from late July,through to September.
Many of the Nightingales caught at the Island Site have been retrapped in the area in subsequent years.
Six males returned to the same net site,one for up to four years;11 settled not far away and two some distance away.Only one female returned to the same net site,four not far away and two at some distance.
There has only been one recovery from the 104 Nightingales ringed.A juvenile ringed on 6th July 1980,was found dead at Maidstone,7 Km to the east on 12th August 1980.Although only a short distance recovery,it does give some idea as to when the juveniles disperse from the area.
Table 2 shows the biometrics of Nightingales trapped at the Island Site,giving details for males,females and juveniles separately.It is interesting firstly,to note the slightly raised weights of the females in May,when carrying eggs ,and secondly the very high weight of the September juvenile.prior to migration.This was matched by an individual at Portland Bill,in autumn 1968,which was first caught on 27th August ,when it weighed 22.8 gm and was finally retrapped on 11th September ,when it also weighed 34.8 gm,an increase of 52.6%. (Clafton 1971).
Although the area has maintained its population of Nightingales for over ten years,it is now reaching the point where some management will be necessary to retain the high density.The willow has become too tall and dense,restricting the light and consequently the growth of the essential ground vegetation.