wild web viewto estimate the spring population of dipper present on the river liza, and to carry...

The River Liza – Gareth Browning April 2015

Bird Monitoring 2015Dipper Cinclus cinclus – River Liza Survey

Peter Ullrich

Ornithological Consultant 25 Arlecdon Parks Road

Arlecdon, FrizingtonCumbria CA26 3XGTel: 01946 861376

email: [email protected]

A report by Peter Ullrich commissioned by The Wild Ennerdale Partnership 2016 Forestry Commission, National Trust, United Utilities and Natural England.

Bird Monitoring 2015River Liza Dipper Survey

Contents

Contents..................................................................................................................... 1Introduction and background.....................................................................................3Methodology...............................................................................................................4Survey Results............................................................................................................5

Dipper Survey of Liza - visit 1 - 07/03/2015............................................................5Dipper Survey of Liza - visit 2 - 14/05/2015............................................................5Summary of survey results.....................................................................................5

Comparison with the 2007 survey..............................................................................5Discussion.................................................................................................................. 7

Summary..............................................................................................................14Recommendations....................................................................................................16Acknowledgements..................................................................................................17Appeal for Records...................................................................................................18Appendix A - The 2015 Surveys...............................................................................19References, further reading and useful links............................................................19Survey Maps.............................................................................................................20

| document.docx | May 5, 2023 |


Introduction and backgroundThis report should be read in conjunction with the base line 2007 Dipper Survey Report which can be found on the Wild Ennerdale website on the Monitoring page http://www.wildennerdale.co.uk/managing/monitoring/ under the “Birds“ section. The 2007 report details interesting historical background data and explores why dipper is important as an indicator of the general health of upland riverine ecology. Much of this is still relevant, but to avoid repetition will not feature in this report.

The Wild Ennerdale project is committed to long term monitoring of 3 key indicator bird species red grouse, ring ouzel and dipper. These iconic species have been chosen as their presence or absence can give us an insight in to the health of the particular habitats that these specialists inhabit. The first surveys were undertaken in 2007.

White-throated dipper Cinclus cinclus (hereafter referred to simply, as dipper) is most commonly associated with fast flowing shallow upland becks and streams, although it can occur in lowland areas if these conditions prevail and providing the water quality is good enough to support an abundant aquatic invertebrate population.

“Dippers breeding at good quality sites may start as early February, but those at high altitudes and/or near acidic streams start later, lay smaller clutches and rear smaller broods than birds on better quality sites. Pairs also rarely attempt a second brood on these poor quality sites” (RSPB).

The establishment of baseline population data for dipper on the Liza at the outset of the Wild Ennerdale Project, and the selection of dipper as a key environmental indicator species are key parts of the long-term environmental monitoring programme for the project area. It was therefore agreed that a baseline survey of dipper be carried out in the spring of 2007 to reliably estimate the number of breeding pairs and their distribution on the River Liza.

The 2015 Dipper survey on the River Liza will compare its findings with the 2007 survey.


http://www.wildennerdale.co.uk/managing/monitoring/


Methodology

To estimate the spring population of dipper present on the River Liza, and to carry this out in a cost effective way, and using the following readily repeatable methodology.

Timing – to walk the River Liza once in March and again in May. If birds are located in May, then extra visits may be required to establish whether they are nesting.

Weather – the survey may be carried out in most conditions but should avoid heavy rain and strong winds.

Location – to walk the length of the Liza starting where the Liza enters Ennerdale Water at 6-figure grid reference NY124144, altitude 113m and ending where the unnamed beck from Beck Head joins the Liza at NY 204115 altitude 360m, a distance in excess of 11km. Keep as close to the banks of the Liza as terrain and undergrowth allow, although it may be impossible to follow the braided river system in its entirety in the vicinity of Low Gillerthwaite.

Any dipper sightings to be recorded using British Trust For Ornithology (BTO) standard notation on to a photocopy of an appropriate scaled map as well as recording sightings of other riverine species such as goosander, common sandpiper, kingfisher and grey wagtail.

A record to be kept indicating whether the water levels in the river are low, normal or high.

If dipper are present, try and establish whether birds are on territory and try to establish if birds are nesting. This may require pausing to be able to study the behaviour of any dipper observed. If no nests are found but foraging adults are present it would be advisable to carry out at least one extra visit to establish whether the bird is a non-breeder.

Use a global positioning system (GPS) to record the survey track and all dipper observations as well as any other interesting riverine species. Enter these locations in to the device by way of a unique waypoint number. Download the track log and waypoints on to Memory Map software and store on a personal computer (PC).

Make hard copies of each survey map which clearly show the findings. At the end of the survey estimate the number of dipper present and the

number of dipper either territorial and/or nesting.



Survey Results

Dipper Survey of Liza - visit 1 - 07/03/2015 (Survey date in 2007 was 15/03/2007)

There were 2 records of dipper, involving different individuals:1) Dipper left boulder at NY158138 and flies downstream.2) Dipper forages in river at NY169134 and flies downstream.

Other riverine species recorded were:1) A pair of mallard at NY141131.


No dipper were recorded on the May survey. As none were present no further survey work was undertaken in subsequent months.

Other riverine species recorded were:

1) Four female goosander resting on a shingle bank - the mouth of the Liza at NY124144.2) A pair of grey wagtail at the “Low Gillerthwaite” footbridge at NY1341413) One male grey wagtail foraging in the main channel of the braided river complex opposite High Gillerthwaite.4) One male grey wagtail foraging in the main Liza channel at NY153139.5) A territorial pair of grey wagtail on Liza – 230m south of Black Sail YHA at NY195122.6) 2 pairs of graylag geese in the vicinity of Gillerthwaite.7) 2 male mallard at Moss Dub at NY146137

Other interesting bird species:

There were 2 registrations of cuckoo in the upper valley beyond the Middle Bridge – heard not seen – see survey map for exact location.

Summary of survey results

07/03/2015 visit 1 – two dipper recorded on the Liza. 14/05/07 visit 2 - no dipper recorded.See maps 1&2 at the back of the report for survey route and sightings.



Comparison with the 2007 survey

Dipper - Ennerdale – photo Gareth Browning – 21/02/2009

No dipper were recorded on the 2007 March survey, whereas two dipper were recorded on the 2015 March survey. This was promising as birds present in the “breeding season” could be regarded as potential colonisers. The sightings were 1.15km apart and on a stretch of river that looks like good dipper habitat, that is one with plenty of boulders and riffles and with a good gradient. However, as the two sightings were essentially “snapshots” the observer would have had to have been extremely fortunate to witness any significant breeding behavior such as singing, courtship or nest building. All that can be said is that two individuals were seen. Further study over the following days would have been needed to establish whether the birds were a pair or separate individuals. The author has noted that dipper are more likely to be encountered on the Liza in winter and early spring than in the summer. This is likely to correlate with the period of peak biomass with more aquatic benthic insects available at this time prior to the emergence of adult insects (Shaw 1978). It is not known whether invertebrate biomass has significantly increased since the 2007 survey. Breeding dipper numbers strongly correlate with good numbers of invertebrates. However, the presence of two dipper indicates that there are some foraging opportunities, at least enough to sustain small numbers of non-breeding dipper at this time of year.

No Dipper were recorded on the May 2015 survey.

In 2007 a dipper was recorded on the May survey. This sighting was highly promising and triggered a series of subsequent surveys to establish whether dipper were breeding on the Liza. These supplementary surveys failed to find any breeding dipper. However single birds were also seen on the 23/06/2007 and 26/06/2007.

If these sightings had been concentrated on a particular stretch of river this would have been highly indicative of a breeding territory. However, the records were well spread out and dispersed over a 3.6km stretch of river.



Only single birds were ever recorded on any of the 2007 surveys and no breeding behavior such as “carrying food” was observed. It is likely that these observations referred to the same single non-breeding individual, which foraged unchallenged along a long stretch of the Liza.

See map 3 at the end of the report which shows all the locations of sightings from the 2007 and 2015 surveys. All sightings were on a 3.7km stretch of river, ranging from NY147138 in the west (140m asl) to NY 179130 in the east (220m asl). The presence of dipper here would indicate that this stretch of river affords the best foraging conditions. As survey work continues we are slowly defining a core area of dipper activity. It is here where we stand the best chance of establishing breeding dipper and this is where conservation efforts should be focused. It has been shown that nest-boxes and nesting tubes provide protection from flooding and mammalian predation, natural nest sites being vulnerable to both these. Providing a safe nesting and roosting site can significantly boost a dipper population providing there is enough aquatic benthic invertebrate food present.



DiscussionI would refer the reader to the Discussion section of the The Wild Ennerdale report Dipper Cinclus cinclus – survey of the River Liza 2007 which can be found on the Wild Ennerdale website www.wildennerdale.co.uk

The effect of water quality and the fact that acidic water holds fewer invertebrates and the implications this has for dipper on the Liza is discussed in the 2007 report. Additionally, it is worth considering the following with regard to recolonisation of the River Liza by breeding dipper:

Sedentary nature of adult dipper and dispersal of juveniles

“Between 1978 and 1986, 2500 nestlings and 700 fledged Dippers were ringed on rivers in mid and south Wales. Adults showed strong fidelity to breeding sites, only 3.6% (of 138) moving more than 2.5km between breeding attempts. By contrast, 30% (of 166) of birds ringed as nestlings moved more than 5km and up to 32 km from natal sites; post-natal dispersal involved significantly greater distances in females than males, with females significantly more likely to cross watersheds” (Tyler and Ormerod 1990).

It is encouraging to see that dipper have now been recorded on both the 2007 and 2015 surveys. The majority of dipper on the River Liza are likely to have dispersed as juveniles from natal sites on the River Ehen. Dipper do breed as “second calendar year birds” and will actively be attempting to establish a territory if conditions are favourable. Essentially many of the birds on the Liza will be one year olds.

Nest sites are traditional, and are used by successive generations of birds. One site is said to have been used continuously for 123 years (RSPB)

The importance of aquatic benthic invertebrates

“The research over recent years into the Dipper population on the Teme can be compared to the invertebrate monitoring data collected over a similar period. There appears to be a direct correlation between the Dipper numbers in the upper catchment where invertebrate numbers are still good, and the lower Dipper numbers in the lower catchment where invertebrate counts are also poor. A similar picture is revealed when assessing habitat, which not surprisingly is better in the upper catchment compared with the lower catchment. This confirms that the Dipper is a very important indicator species in the health of the river, its ecology and ecosystem” (Tony Bostock, Director Severn River Trust, pers.comm. 2012 from the Dippers Cinclus cinclus In the River Teme Catchment report 2010).

Winter distribution of dipper

Ennerdale Water is oligotrophic, that is low in nutrients. Dippers will feed by oligotrophic lake shores especially outside the breeding season (Tyler and Ormerod - The Dippers – 1994). The previous statement is borne out by Wetland Bird Survey (WEBS) data from Ennerdale Water, a monthly survey undertaken by the author to monitor non-breeding waterbirds. It is part of a



UK wide scheme run by the BTO. During the course of these surveys dipper are frequently seen foraging along the lakeshore outside the breeding season, but are found less frequently in the breeding season. The author has noted that when the river Ehen is in spate there is more chance of seeing dipper foraging along the lakeside. Presumably lakeside foraging during flood events is easier and more productive than on a deep fast flowing river.

Data from “Bird Atlas 2007-11 (BTO)” also illustrates the difference between winter and summer abundance of dipper in Ennerdale. Atlas work for 10 km sq NY11 was carried out by the author (10km sq NY11 does not cover the full area of Ennerdale Water. It covers more than two thirds of the lake’s area and lakeshore; that is everything west of the Northing NY10 that bisects Anglers Crag). Summer survey work found no dipper on the Lake or up the Liza valley, but winter survey work recorded dipper in 4 Lakeside tetrads NY1016, NY1014. NY1214, and NY1212.

Dipper are frequently seen on the lake in the winter. A favourite location to see non-breeding dipper is in the bay adjacent to Smithy Beck. This is only 200m from the mouth of the River Liza. The author has seen the odd bird on the Liza in winter, the most unusual record being a dipper recorded foraging at Moss Dub (tetrad NY1412) on 18/01/2009 which was a very surprising location given the stagnant nature of the pond.

Traditional nest site at scout camp footbridge on the River Ehen and its history

The closest traditional dipper nest site to the River Liza is on the River Ehen. The nest site is under the footbridge which is located 50m west of the lake weir at grid reference NY088153, and is at the very start of the River Ehen. This footbridge will be referred to as the scout camp footbridge from now on.

Listed here are some of the more interesting records from scout camp footbridge indicating breeding or territorial activity (None of these records are part of a systematic survey and are taken from the authors notebook):-

o 25/04/2004 – dipper visits nest under bridge.o 15/07/2005 – adult dipper with 2 recently fledged juveniles in

attendance begging for food.o 01/03/2008 – female dipper nest building, and carries nest material to

nest under footbridge, male sings nearby.o 13/04/2008 – dipper takes food to nest (confirming breeding)o 22/03/2009 – dipper leaves nest under footbridgeo 04/05/2009 – dipper takes food to nest.o 11/02/2011 – dipper visits nest site under footbridge.o 21/02/2011 – dipper nest building and carries nest material to nest.o 13/03/2011 – dipper leaves nest under footbridge.o 18/11/2011 – 2 dipper present on river near footbridge, first time here

for some considerable time - birds did not successfully breed this year.o 18/04/2012 – dipper sings near scout camp footbridge.o 25/04/2014 – A pair, one investigates nest site under footbridgeo 29/04/2014 – dipper leaves nest site under footbridge.o 01/06/2014 – 1 present after an absence of 5 weeks – birds did not

successfully breed this year. Note: It is not known whether large scale



works to reinstate Ben Gill impacted on breeding success this year, a bird was not noted again until 05/09/2014 and was then regularly present for the rest of the year.

o 25/02/2015 – dipper pair present, however no activity at the nest site was noted this season – the last time a dipper was seen at this location was a single bird on 01/04/2015. None were seen through the summer and autumn months despite frequent visits - 31 visits from 07/04/2015 to 09/11/2015.

Winter territory at Scout camp footbridge

“In Britain many observers have reported dippers showing territorial behavior in the winter. Murphy (1972) found winter territories to be established in September to October and to exist until February or even March. In much of our study area, winter territories are very similar to breeding territories, the two often coinciding, with many pairs remaining on the same stretch of 500-1000m of river for the whole year. There are some single birds during the winter, some of these occurring on rivers where breeding does not occur. On poor quality, acidic streams winter abundances are low, c. 0.25 birds/km; elsewhere in Wales there may commonly be 2-3 birds/km.”(Tyler & Ormerod 1994)

. At the scout camp footbridge site, in years when a breeding attempt is short-

lived and unsuccessful, birds are often absent through June, July and August with dipper reappearing in the autumn. In 2014 the last record of dipper in the breeding season was 1 present on 01/06/2014, 11 subsequent visits over the summer were made without success until one was seen on 05/09/2014. Dipper were then present on and off throughout the winter with the formation of a pair observed:-

o 10/11/2014 & 11/11/2014 – dipper sings near scout camp footbridgeo 19/11/2014 – territorial bonding - 2 birds involved in pursuit flight, is

likely to indicate formation of a pair.o 27/11/2014 – pair present, birds side by side.

Colonisation of river Liza by dipper from river Ehen

As previously noted the scout camp footbridge on the river Ehen is the closest known “traditional nest site” that is within the same watershed as the river Liza. Without extensive systematic surveys in adjoining watersheds it is not known whether there are any nest sites closer to the river Liza and whether colonisation from outside the valley is at all likely.

The last time fledged dipper were seen by the author at the scout camp footbridge breeding site was in 2005. However successful breeding over the intervening years cannot be totally ruled out as the authors records are of a casual nature.

Logic would dictate that a healthy population on the river Ehen would be fundamental in any recolonisation of the river Liza by dipper.

As adult dipper are highly territorial and sedentary in nature, they are not likely to move great distances from a traditional territory, therefore any recolonisation of the river Liza is likely to involve dispersal of juveniles from



the Ehen population. Distance from scout camp footbridge to the mouth of the river Liza 3.7km

The River Ehen from its outfall at the Lake to its confluence with the River Keekle is a Special Area of Conservation (SAC). The River Ehen is also a Site of Special Scientific Interest (SSSI), it holds the largest population of fresh water pearl mussel in England and this is the primary reason for it qualifying as a SAC.

A formal assessment of SSSI condition was carried out during 2012 following the low-flow incident resulting in high levels of stress and mortality in the mussel population. This assessment considered that the River Ehen was in unfavourable declining condition. The assessment was made largely on the basis of the declining condition of the freshwater mussel population as the primary interest feature of the river SSSI/SAC, reflecting the issues relating to abstraction, compensation flows and diffuse sources of pollution (siltation and nutrients) but in particular the lack of juvenile recruitment sufficient to sustain the population. (Natural England)

“Pearls in Peril” (PIP) is a four year project and will run from 2012 – 2016. It aims to reverse the fortunes of the declining and endangered fresh water pearl mussel (FWPM). As part of the overall plan to conserve the vulnerable and declining Ehen pearl mussel population, Ennerdale will cease to be used as a water source with abstraction ceasing in 2025. Other conservation measures will involve changes in land management such as taking land out of agricultural production, identifying and mitigating against the impact of point source pollution and diffuse pollution. Whilst these measures and others are primarily aimed at improving conditions for the fresh water pearl mussel and salmon population it is clear that these actions will be highly beneficial for the dipper population on the River Ehen which like FWPM are dependent on good water quality (well oxygenated oligtrophic conditions) and act as excellent indicators of water quality.

At the time of “The Breeding Birds of Cumbria a tetrad atlas 1997-2001” the stretch of the River Ehen which lies in 10km sq NY01 had dipper records at six locations. Data from the “Bird Atlas 2007-11” (BTO) indicates that dipper were recorded from 4 locations during the breeding season. This would appear to show a decline in dipper over the intervening 10 years, but extreme caution must be taken in comparing atlas data from one atlas to another as they are generic surveys covering all bird species, with the observer free to choose any route they want in a tetrad (2km sq), so coverage of water courses can be drastically different from one survey to another. A fundamental problem for surveying dipper on the River Ehen is the lack of public access which is very limited along its length.

Specific dipper records on the River Ehen SAC other than those noted at Scout camp footbridge are few and far between. Notable is a long established traditional nest site on the River Ehen adjacent to Longlands Pond, Cleator. This site is also associated with a footbridge (grid ref NY01281294). The county natural history report “Birds in Cumbria” notes successful breeding here in 1998 and 2000. Here are all the records that could be found. They are a combination of “Birdtrack” records from the BTO recording site and records supplied to the author by ornithologists :- 07/12/2008 – 1 dipper - Salter Wood - NY056161 - (record Barbara Nelson)14/03/2013 – 2 dipper – Nr “Hen bridge” – NY032144 – (record Phil Espin)



31/05/2015 – 1 dipper – adjacent to Longlands pond – (record Jane Dyer)

It is worth noting that the paucity of records is more likely to reflect the lack of public rights of way along the River Ehen and therefore records have a heavy bias towards areas with good public access, especially bridges.

The importance of bridges for nesting dipper and the provision of nest- boxes

A BTO analysis was undertaken by Geoffrey Shaw of 1,356 nest record cards, the bulk of these from the time period 1952 – 1972. 62% of these were from northern England. 1,159 of these gave a detailed description of the nest site. 573 were on manmade structures (49.4%) and 400 of these were on bridges (34.5%). It is recognized that nests under bridges are easy to find, which brings a potential bias in the analysis of the nest record cards.(Shaw 1978)

In a study of dipper in SW Ireland most nests (86% of 479) were built on artificial structures, virtually all of them on bridges (Smiddy, O'Halloran, O'Mahony& Taylor 1995).

Tyler & Ormerod (1994) suggests that on most upland streams it is unlikely that nest or roost sites could limit breeding dipper as there are many rocky banks and overhanging trees and banks providing nesting and roosting opportunities. On the lower reaches of streams where banks are low and rocky faces and riverside trees are absent, bridges and walls are important often permitting dipper to breed in high abundance. In their Welsh study site 72% of 252 nests were artificial sites, mainly ledges and girders under bridges. The study also found that where birds had a choice, bridges were chosen over natural sites.

In many studies bridges are regarded as fundamental to breeding dipper. A lack of bridges and therefore nest sites, limiting the dipper population. In Germany, Rockenbauch (1985a) believed that bridges were essential if high dipper abundancies were to be maintained on the river system that he studied. Many modern bridges particularly concrete bridges do not provide any ledges or cracks and do not provide any nesting/roosting opportunities for dipper the solution here is to provide a nest box under the bridge. One study in Germany where good nest sites were lacking increased the dipper population from 1 pair to 14 pairs when nest-boxes were provided (Staedtler and Bremshey 1988). Another German researcher claimed that population increases after the provision of 200 nest-boxes was not due to a lack of natural sites but to higher breeding success because the nest-boxes were much safer (Kaiser 1988). (Tyler & Ormerod)



Dipper nest box under footbridge

Nest-boxes can mitigate against the impact of mammalian predators. They can be positioned so that even in times of flood events they do not get washed away (Above usual flood heights).

Nesting tubes can be used on bridges that are susceptible to flooding and unlike wooden nest boxes do not get washed away. A good example of the proactive use of nest boxes is a scheme attempting to reverse dipper declines on the River Teme catchment in Shropshire. They are finding that large scale deployment of nest-boxes is a useful tool to improve breeding success and boost the breeding success of a declining population. The decline is attributed to a loss of food as a result of reduced quality of the rivers, primarily due to pollution from, and silting up by agricultural activities. “Recollections from many years of monitoring Dippers (on the River Teme catchment) suggest that the level of nest success in natural sites on riverbanks, or amongst boulders in the streams, is much lower than those under bridges, as they are more vulnerable to flooding or predation”. More Dippers were found in 2008 and 2009 than in any previous year. This is attributed to an increase in the number of nest sites and improved breeding success, in the upper reaches of the rivers as a result of the nest boxes. (Cross, Swift & Smith from the 2009 Dippers in the River Teme Catchment report).



Dipper nest box - Lithiadipperwatch Human disturbance

In the Derbyshire Peak District increasing disturbance by insensitive photographers has been blamed for a fall in survival rates of nesting dipper at one or two key dipper sites which has had a direct and negative impact on their nesting in recent years. As a result Natural England produced a leaflet with guidelines for photography.

In our national parks recreational activity in key beauty spots has increased hugely over the last twenty years. Some traditional dipper nest sites in Derbyshire adjacent to increasingly busy footpaths no longer see successful breeding attempts. The cumulative impact of heavy and unrelenting pedestrian flow results in the abandonment of these sites. In order to mitigate against this a number of “dipper nest tubes” were located away from paths or obvious picnicking places. In 2014 a pair were seen nest building at one of these tubes which had been provided a couple of years earlier.

Dipper nesting tube Derbyshire

The traditional nest site at “The Scout camp footbridge” has seen less dipper activity in recent years. The reasons are uncertain and potentially complex. It might be as a result of several factors with a resulting cumulative impact. What has changed at this site in recent years? The most recent change at this site has been the reinstatement of Ben Gill in 2014, the resulting shingle bank being a new feature only c30 m upstream of the traditional nest site. Dipper like running water under their nest, the flow regime past the traditional nest site has certainly altered especially when Lake and river water levels are low. At such times there are very low flow levels directly below the nest site (which is always located on the south end of the bridge where it meets the wall). It would be impossible to definitely link recent changes to Ben Gill with lack of dipper activity at the Scout camp footbridge, but it might be a contributory factor, one piece of the jigsaw.



Pedestrian numbers crossing the footbridge have also increased in recent years, especially with the new Broadmoor circuit providing a convenient 30 minute circuit for dog walkers. Whether or not the increase in footfall is at a level to be a significant disturbance factor is unknown. These two changes are factors that can” readily be seen” and may or may not have a detrimental impact on breeding dipper at this site. Other factors at play which are not readily visible might relate to availability/quality of food along this stretch of the River Ehen, to establish whether this is the case or not an analysis of past and present aquatic benthic invertebrate surveys would have to be undertaken.

Mammalian predation of roosting or nesting birds may be another unseen factor.

A systematic dipper survey of the River Ehen has never been undertaken. The lack of breeding dipper at scout camp footbridge might be indicative of a general population decline on the Ehen.



SummaryNo breeding dipper were found. However, the March survey recorded 2 different individuals 1.15km apart which was promising, especially as they were present at the start of the breeding season on a stretch of river that looked like good dipper habitat. It was impossible to establish whether these sightings involved a pair, so without any firm evidence they are best regarded as two individuals of unknown sex. Unfortunately, the May survey was a nil return and the fortunes of the two March dipper are unknown.

Many studies unsurprisingly show a direct correlation between a plentiful food supply and successful breeding and abundance in dipper. In the absence of detailed data regarding whether aquatic benthic invertebrate populations are recovering in response to conifer clearing in the eastern valley and replanting with deciduous trees, it is promising that the 2007 and 2015 surveys both confirm that at the very least the River Liza can support foraging dipper in the breeding season. What is not known is whether the aquatic benthic invertebrate population is sufficient to support a pair of breeding dipper, this activity requiring increased energy consumption (food) to lay eggs and fledge young successfully.

Like many Lakeland rivers the River Ehen is prone to large rises and falls in water levels. It is generally believed that flood events are on the increase due to changing climatic conditions. Dipper nesting in natural locations under banks and tree roots are vulnerable to flood events and are susceptible to mammalian predation. Bridges are very important as nest sites and provide protection against flood and predation. However, many modern bridges do not have girders or ledges where nests can be built. Numerous schemes aiming to increase dipper populations have found that the provision of nest-boxes or nesting tubes under bridges can significantly help the population by increasing the number of pairs and their breeding success. It is also possible to mitigate against increased footfall at particularly busy bridges, where unintentional human disturbance can have a detrimental impact on dipper breeding success by providing an alternative artificial nest site nearby but in a quieter location.

The majority of dipper seen on the River Liza are likely to have originated from the river Ehen and its tributaries. So potential colonisation of the Liza is dependent on a healthy dipper population on the Ehen. Yet the extent of this population and its breeding success is unknown.

The River Ehen holds the best population of Fresh Water Pearl Mussels (FWPM) in England. Following a formal assessment of the conservation status of the 13km of the River Ehen SAC in 2012 its condition was described as “unfavourable” and in “declining condition”. Mainly because the long term survival of the population was under threat. Dipper and FWPM can both be used as barometers of riverine habitat. Dipper can play a vital role as a key indicator species as the concerted effort gets underway to restore the SAC to favorable condition.



RecommendationsAs a key indicator species of water quality, repeat the River Liza survey every five years.

Instigate a study of bridges on the River Liza and its tributaries and assess their suitability for nest box provision. Assess whether stretches of river away from manmade structures would also benefit from nest box deployment. Results from the 2007 and 2015 surveys show that all dipper sightings in the breeding season on the River Liza are on a 3.7km stretch of river (See map 3). This should be where conservation efforts are focused. Candidate bridges that might benefit from nest-box deployment in this area are Middle Bridge and Memorial Bridge as well as the lower forest track bridges over Low and high Beck.

A healthy dipper population on the River Ehen is the key to any possibility of recolonisation of the River Liza. However, no species specific dipper survey has been undertaken of the breeding population on the River Ehen SAC. Carry out annual dipper surveys in March for a period of three years. This would provide reliable population data for dipper and would provide a mean population index, taking in to account any variability from year to year. Then assess whether there are any stretches of river that would benefit from the provision of nest boxes or nesting tubes and continue annual monitoring to see whether the dipper population is boosted by providing safer nest sites.

Carry out regular monitoring of the aquatic benthic invertebrate population on both rivers such that the health of the invertebrate population can be assessed.

A camera trap could be set up at the Scout Camp footbridge nest site to monitor any dipper activity and mammalian activity – as rats or other mammals could be predating roosting or nesting birds.



AcknowledgementsThe author would like to thank the following who contributed records and photos used in this report; Gareth Browning, Barbara Nelson and Phil Espin. Also many thanks to the help and support provided by Gareth Browning (Forestry Commission), Rachel Oakley (National Trust), Dave Shackleton (Cumbria Bird Club) and Simon Webb (Natural England).



Appeal for RecordsTo improve our knowledge of birdlife in Ennerdale, The Wild Ennerdale project would appreciate any records of the 3 key target study species: red grouse, dipper or ring ouzel. Please provide a six figure grid reference and date of sighting. Any photographs would be gratefully received. Details can be e-mailed directly to the author at [email protected] or directly to The Wild Ennerdale Partnership.



Appendix A - The 2015 SurveysDipper Survey of Liza - visit 1 - 07/03/2015 (Survey date in 2007 was 15/03/2007)

• Start - mouth of Liza at 6 figure grid ref NY124146 – 08:58hrs (GMT). • End - where unnamed beck from Beck Head joins Liza at 6 figure grid ref

NY204115 – 12:55hrs (GMT). • The riverbank was followed as closely as possible throughout the survey to

ensure the watercourse was thoroughly covered. Refer to GPS track log on survey map for exact route.

• Survey duration 3hrs 57mins (11.2km) • The return trip down the valley was not part of the survey. The return was

made via the forest track on the north side of the Liza.

Weather Conditions • Exceptionally mild. • Wind SW force 6. However in reality the wind strength along the Liza is much

less due to the shelter provided by the local fells and trees. Leaving the forest the wind increased. The wind was funneled down the valley from aptly named Windy Gap and was a SE force 7/8 gusting at the very end of the survey to SE force 9.

• 100% cloud cover with the cloud base at around 300m.• Visibility 5-10km

Liza water level • Normal, no turbidity


Start - mouth of Liza at 6 figure grid ref NY124146 - 10:00hrs (BST). • End - where Beckhead beck joins Liza at 6 figure grid ref NY204115 –

13:56hrs (BST). • The riverbank was followed as closely as possible throughout the survey to

ensure the watercourse was thoroughly covered. Refer to GPS track log on survey map for exact route.

• Survey duration 3hrs 56mins (11.2km). The return trip down the valley was not part of the survey. The return was made via the forest track on the north side of the Liza.

Weather Conditions • Sunny.• Wind ESE F4 but much less in sheltered forest. • 40% high cloud cover with the cloud base above the local fells.• Visibility >30km

Liza water level • Normal, no turbidity



References, further reading and useful linksS. J. Tyler & S. J. Ormerod (1994) The Dippers, T&D PoyserGeoffrey Shaw (1978) The Breeding Biology of the Dipper, Bird Study, 25:3,149-160

S. J. Tyler , S. J. Ormerod & J. M. S. Lewis (1990) The post-natal and breeding dispersal of Welsh Dippers Cinclus cinclus , Bird Study, 37:11, 18-22,

R Hewson Territory, behaviour and breeding of the Dipper in Banffshire, British Birds, 60.6,244-252.

P. Smiddy , J. O'Halloran , B. O'Mahony & A. J. Taylor (1995) The breeding biology of the Dipper Cinclus cinclus in south-west Ireland, Bird Study, 42:1, 76-81,

Cross, Swift & Smith (2010) Dippers Cinclus cinclus, In the River Teme Catchment, 2009 report

Cross, Swift & Smith (2013) Dippers Cinclus cinclus, In the River Teme Catchment, 2011 & 2012 report

Balmer, Gillings,Caffrey,Swann,Downie& Fuller (2013) Bird Atlas 2007-11 The breeding and wintering birds of Britain and Ireland, BTO

Pearls in Peril LIFE+ GB Action A3: Conservation Actions for the Freshwater Pearl Mussel in the River Ehen, Cumbria September 2013-2016 West Cumbria rivers Trust

Birdtrack (BTO) http://app.bto.org/birdtrack/main/data-home.jsp - A map based recording system for birds

Cumbria Biodiversity Data Centre http://www.cbdc.org.uk/bird-atlas-maps -Detailed maps from Bird Atlas 2007-11 The breeding and wintering birds of Britain and Ireland, BTO records collected by Cumbria Bird Club, BTO and other dedicated lovers of Cumbrian birds.


http://www.cbdc.org.uk/bird-atlas-maps

http://app.bto.org/birdtrack/main/data-home.jsp


Survey Maps


wild web viewto estimate the spring population of dipper present on the river liza, and to carry...

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