North Pennines black grouse population down 40% in 2 years

08/04/2009 00:49:37 Weather fears could hamper rare black grouse revival in northern England
April 2009. Two years ago scientists from the Game & Wildlife Conservation Trust and project partners of the North Pennines Black Grouse Recovery Group, were jubilant that the rare black grouse had exceeded its Biodiversity Action Plan target ahead of schedule with 1,200 males recorded in 2007. However, the past two years have witnessed the worst summer weather conditions for almost 18 years and this has caused a major set-back in the recovery of this iconic species. It is now feared that the North Pennines black grouse population after making a good recovery in numbers may have fallen back to 850 males.

Dire weather restricting successful breeding
Dr Phil Warren, Project Officer for the North Pennines Black Grouse Recovery Project said, "We have had two poor breeding years as a result of cold wet weather in June when the chicks hatch. As a result breeding productivity in both years was well below the 1.2 chicks per hen required to maintain a stable population. Weather conditions in June are a major factor limiting the recovery of black grouse populations. Therefore, it is imperative that when the weather conditions are favourable, we maximise breeding productivity by providing brood-rearing habitats rich in insects, particularly sawfly larvae, and the effective control of predators, such as stoats."

Scientists from the Game & Wildlife Conservation Trust have said that appalling summer weather for the past two years has caused a major set-back in the recovery of rare black grouse and they have predicted that numbers might fall to below 850 males. Credit Bruce Adams.

Extend the range
As part of the recovery process, the next phase was to attempt to expand the range of black grouse into former haunts. Although some progress has been made towards expanding the range of this spectacular bird, this has also been seriously hampered by poor breeding productivity and translocation trial work has been postponed because the technique is reliant on moving a surplus of males in good breeding years.

Worse in Scotland?
But although these gloomy prospects for black grouse in the north of England are a huge blow to all the project partners, Dr Warren says. "These simple statistics outline the importance of conserving populations at levels which can withstand these periodic random factors such as weather. Our black grouse population in northern England is sufficiently large enough to withstand two or three years of such poor breeding. However, of greater concern is the impact of these random occurrences on small fragmented populations, typical of those found in south-east Scotland."

Species fragmentation
In south-east Scotland, the last UK survey indicated a 69% decline in the last 10 years, with the population estimated at only 257 males in 2005. Dr Warren explains, "Applying our statistics of virtually no young being recruited into the population over the past two years and average annual mortality rates of full grown birds of 70%, then it is likely that the average lek size of three males found here will have declined to just one male, and the population may now only number 150 males. From a population fragmentation viewpoint and overall level, this is now critical and a further two years of poor breeding could result in a virtual extinction of black grouse in south-east Scotland. With similar declines predicted in south-west Scotland this could leave a gap of 150 miles between birds in northern England and those in Perthshire.

The Game & Wildlife Conservation Trust and the RSPB are joint lead partners for the Government's Biodiversity Action Plan for black grouse, and established the North Pennines Black Grouse Recovery Project 12 years ago as a partnership project between the Game & Wildlife Conservation Trust, Natural England, RSPB, Ministry of Defence, North Pennines AONB Partnership and Northumbrian Water. To date, it has been one of the most successful bird restoration projects in this country.