Partridge Count Scheme

Partridge & Biometrics

JOIN THE PCS

The country’s wild grey partridges need more land managers, especially those with only a few grey partridges, to join the Partridge Count Scheme. Find out more at www.gwct.org.uk/pcs.

Partridge Count Scheme

The number of grey partridge pairs recorded in the spring of 2019 was 7,406, with a 41% increase in density since spring 2018. © Steve Round

KEY FINDINGS

The national average spring pair density on PCS sites increased by 41% in 2019.

Summer productivity, measured as Young-to-Old ratio, fell to just two young birds per adult.

Nationally, the average autumn density decreased by 11%.

Neville Kingdon Julie Ewald

Partridge Count Scheme (PCS) members returned 561 counts in spring 2019, an encouraging increase of 84 spring counts from 2018. A total of 7,406 pairs of grey partridge were counted across 174,500 hectares (ha) (431,100 acres). Average spring pair density nationally increased by 41% to 5.2 pairs/100ha (250 acres) (see Table 1). Eastern England witnessed the greatest increase in pair density. North England and Scotland each recorded positive increases as did the few participating areas in Wales and Northern Ireland. Meanwhile, the Midlands experienced a decline (-10%) but still achieved an average 2.6 pairs/100ha, but southern England suffered the largest decrease (-21%) to an average of just 1.5 pairs/100ha.

Nationally, over-winter survival (OWS) for 2018/19 decreased again (-7%) to 49%. Northern England was the only region to see an increase in OWS (13%). Scotland and southern England’s OWS remained relatively stable with only small declines (less than -2%), but OWS in eastern England declined again for a second year (-20%), now achieving only 43% survival.

The long-term change in spring pair density (see Figure 1) shows that sites which participated in the PCS prior to 1999 (long-term sites) recorded an average 19% increase on the 2018 spring density, giving an average 2019 spring density of 5.7 pairs/100ha, while new sites (which joined since 1999) recorded an increase of 18%, with an average density of 3.6 pairs/100ha.

The noticeably warm dry spring offered hope of a good summer for wild partridges, but as June began Storm Miguel dragged in successive bands of wet weather to most areas for the rest of the month, hitting just as mid-June’s peak hatch occurred. This inclement

Figure 1 40

Trends in the grey partridge spring pair density, controlling for variation in different count areas

Long-term sites

New sites

ACKNOWLEDGEMENTS

We are extremely grateful to GCUSA for its ongoing support of our grey partridge work.

Spring grey partridge pairs per 100 hectares (95% CL)

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15

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TABLE 1

Grey partridge counts

Densities of grey partridge pairs in spring and autumn 2018 and 2019, from contributors to our Partridge Count Scheme

Number of sites Spring pair density Number of sites Young-to-old ratio Autumn density (spring) (pairs per 100ha) (autumn) (autumn) (birds per 100ha)

Region 2018 2019 2018 2019 Change (%) 2018 2019 2018 2019 2018 2019 Change (%)

South 63 81 1.9 1.5 -21 82 74 1.9 1.8 9.9 8.8 -11 East 146 175 5 9.1 82 151 125 2.7 2.1 22.2 25.5 15 Midlands 85 103 2.9 2.6 -10 94 87 2.4 1.8 19.6 11.7 -40 Wales 2 2 0 1.5 150* 2 2 - - 0 0 0 North 109 123 4.8 6 25 114 112 3.0 2.2 34.2 28.7 -16 Scotland 71 76 2.2 2.6 18 71 70 2.5 2.2 11 10.9 -1 N Ireland 1 1 7.9 9.9 25* 1 1 1.0 0.8 13.3 22 65* Overall 477 561 3.7 5.2 41 515 471 2.6 2 20.7 18.5 -11

* Small sample size. The number of sites includes all those that returned information, including zero counts. The young-to-old ratio is calculated from sites where at least one adult grey partridge was counted. The autumn density was calculated from sites that reported the area counted.

weather, just at the wrong time, compounded any effect that the UK Government’s earlier withdrawal of the General Licence would have had on nesting success.

The PCS received 471 autumn counts, 9% fewer than were returned in autumn 2018 (see Table 1). The total number of grey partridges recorded nationally was nearly 19,200, a drop of more than a quarter of the numbers recorded in autumn 2018. The national autumn density declined by 11%, from 20.7 birds per 100ha in autumn 2018 down to 18.5 birds per 100ha. Regionally, only eastern England increased its autumn grey partridge density.

Despite the frustrating summer, especially after such a promising spring count, PCS participants did report very young second or late broods, which look to have offset the worst of June’s losses. The national average Young-to-Old ratio (YtO), which is an easy measure of summer partridge productivity, reached two (down 30% from 2.6 in 2018). Thankfully, despite the poor June weather, nationally productivity still exceeded a YtO of 1.6 – the minimum level required to cover adult losses into the following year. Regionally, Scotland, northern and eastern England regions achieved the highest YtO in 2019, although all regions saw declines in their grey partridge summer productivity, especially for northern England, the Midlands and eastern England.

Adverse summer weather cannot be prevented and is probably something we will face more often, but this summer’s partridge productivity could have been much worse without the habitats and management PCS participants have in place, helping to minimise their losses. However, to help maximise brood survival in both good years and bad, more farms and shoots throughout the country need to address this aspect of the partridge life cycle by providing suitable nesting cover, with nearby brood-rearing habitat to provide the chick-food insects that are of paramount importance early in life. BACKGROUND

Partridge counts can offer valuable insight into how well your partridges breed, survive and benefit from your habitat and management provision throughout the year. Each count (spring and autumn) is easy to carry out and helps assess the previous six months without the need for continual monitoring. How to count:

Record what partridges you see – using binoculars helps when examining each pair or covey.

Spring: Ensure winter coveys have broken up and breeding pairs have formed – typically in February and March. Record all pairs and any single birds.

Autumn: Wait until most of the harvest has finished – ideally between mid-August and mid-September. Record adult males, adult females and young birds in each covey separately. Don’t assume a covey is two adults and some young.

Use a high 4WD to drive around fields and then criss-cross the whole field to check the entire area, using the tramlines to minimise crop damage. www.gwct.org.uk/pcs.