BIOMETRICS & PARTRIDGES - ROTHERFIELD DEMONSTRATION PROJECT |
TABLE 1 Year
Gamebird recovery at Rotherfield, split between the Trust and Estate side Spring pairs
Autumn stock Trust
Grey partridge 2016 (2015)
Red-legged partridge 2016 (2015)
Pheasant* 2016 (2015) Hens
Cocks 19 (22) 38 (37) Estate Total 3 (7) 24 (53) 22 (29) 62 (91)
180 (220) 131 (135) 311 (355) 185 (147) 109 (133) 294 (280)
Trust 69 (48) Estate Total 3 (20) 76 (116) 74 (67) 72 (68) 150 (183) 481 (348) 214 (174) 695 (522)
*For pheasants, spring pairs is the number of wild females encountered; autumn stock is the number of cocks, hens and young combined (released cocks excluded). On the Trust side, 600 cock pheasants were released each year since 2011.
age of grey partridge pairs producing young averaged 66% on the Trust side, 32% on the Estate side. For pheasants, the average number of young per hen counted in autumn was 2.0 on the Trust side, whereas it was 3.3 on the Estate side. Nevertheless, gamebird recovery on the Estate side has improved little since the project began, whereas on the Trust side, recovery is making slow but steady progress. Farmland songbirds of conservation concern such as yellowhammer, skylark and
linnet, have also increased by an impressive 66% (77% on the Trust side, 49% on the Estate side), illustrating the benefits of grey partridge management for an otherwise nationally declining group of birds.
Songbirds of conservation concern have increased 77% on the Trust side. © Markus Jenny
BACKGROUND
The project started in 2010 to demonstrate grey partridge recovery from zero, together with the benefits for other wild game and wildlife. It aims to be applicable to a wide range of landowners and other stakeholders wishing to recover grey partridges where they have gone extinct. Grey partridge reintroduc- tion is based on GWCT guidelines, which follow international principles.
TABLE 2 Hen breeding survival*, young per hen in autumn and percentage of successful pairs/hens** Grey partridge***
Baseline year 2010 2011 2012 2013 2014 2015 2016
Avg (SE) 2011-2016
Pheasants Baseline year 2010 2011 2012 2013 2014 2015 2016
Avg (SE) 2011-2016
Hen breeding survival (%) Trust
Estate
23.5 25.0 57.1 50.0 69.2 59.1 94.7
59.2 (9.3)
18.7 45.1 45.6 52.4 41.1 48.2 67.8
50.0 (3.9) released (98% of spring birds were wild) in 2016.
www.gwct.org.uk GAME & WILDLIFE REVIEW 2016 | 33
71.4 87.5 12.5 30.0 36.4 57.1 33.3
42.8 (10.7)
25.0 64.1 16.5 66.7 42.3 25.9 34.4
41.6 (8.3)
Young per hen in September Trust
Estate
1.8 1.7 0.8 8.8 7.9 1.4 2.0
3.7 (1.5)
2.7 2.3 1.0 2.5 2.1 1.6 2.2
2.0 (0.2)
2.4 1.1 0.0 1.7 0.8 2.8 0.0
1.1 (0.4)
2.3 4.9 3.4 3.1 2.3 3.3 2.7
3.3 (0.4)
Successful pairs/hens (%) Trust
Estate
25.0 66.7 12.5
100.0 100.0 38.5 55.6
66.4 (14.1)
12.3 22.4 17.1 32.5 28.6 28.6 43.3
28.8 (3.7)
20.0 28.6 0.0
66.7 50.0 50.0 0.0
32.5 (11.4)
23.0 45.3 15.2 39.7 34.1 24.4 23.7
30.4 (4.6)
*Percentage of spring hens still seen in autumn, **Percentage of pairs (grey partridge) and hens (pheasant) counted in the autumn that produced a brood, ***In grey partridges approximately 76% of breeding birds were reared released (24% were wild) in 2010, whereas only one breeding cock was reared
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