Policy paper

Annex A1: updating minimum and maximum numbers during 2022 badger control operations

Published 5 April 2023

Applies to England

Background

In 2022, as in previous years, it became apparent from daily data collected through the course of badger control operations and actual circumstances being observed in the field, that there was a wider variation in badger abundance across the control areas than it had been possible to estimate prior to the control operations. Specifically, some badger control companies were encountering and removing more badgers than expected and some were seeing and removing fewer despite equivalent amounts of effort deployed by similarly trained contractors.

This necessitated updating of the minimum and maximum numbers for 39^{[footnote 1]} control areas following the advice published by Defra in October 2022 (Section D)^{[footnote 2]}.

Updating numbers in Areas 33 to 53 and 55 to 74

The method used to update the minimum and maximum numbers has not been changed since 2017 but has been improved to take into account further data from effective first year control areas^{[footnote 3]} and effective second, third and fourth year control areas in previous years.

For all areas the minimum and maximum numbers were recalculated using an historical comparator. Taking data from the previous years’ effective control areas, the proportion of the Day 42 cull total that was achieved on each day in each area is calculated, then averaged across areas to generate the historical comparator. This allows the prediction of the expected Day 42 total for any area, from any given day. The minimum and maximum numbers are then set equidistant around the expected cull total. In 2022 there was a 24-hour optional pause in operations on the day of the Her Majesty’s State Funeral. Effort calculations were based on 43 operational days of data for this year only.

The updated minimum and maximum numbers in 26 areas^{[footnote 4]} were further increased by 1.5% per operational day, to account for their desire to continue beyond 43 days in order to maximise disease control on land parcels where factors such as late maize harvest or poor weather conditions hampered coverage.

The data used to calculate the minimum and maximum numbers is taken from Day 28 of operations and this data and the resulting updated numbers are presented in Table 1.

In the first week of the operations it became apparent that in 2 areas there were considerably more badgers than the initial sett survey population estimate had suggested. The numbers were therefore updated in Area 41 – Staffordshire to a minimum of 251 and a maximum of 341 and in Area 63 - Cornwall to a minimum of 392 and a maximum of 532 using the methodology explained above. These numbers were updated again based on data from Day 28.

Table 1: Data for updating minimum and maximum numbers in Areas 33 to 72 during 2022 badger control operations^{[footnote 5]}

Area	Day	Effort	Badgers removed by Day 28	Updated minimum number	Updated maximum number
Area 33 - Avon	28	71	250	282	382
Area 34 - Cheshire*	28	72	544	609	827
Area 35 - Cornwall*	28	68	498	544	739
Area 36 - Staffordshire*	28	61	198	225	305
Area 37 - Devon*	28	66	249	278	378
Area 38 - Devon*	28	70	311	341	463
Area 39 - Dorset*	28	68	186	205	279
Area 40 - Herefordshire	28	63	476	523	710
Area 41 - Staffordshire*	28	71	265	291	394
Area 42 - Wiltshire*	28	62	1113	1285	1744
Area 43 - Wiltshire	28	65	400	455	617
Area 44 - Avon*	28	62	653	729	990
Area 45 - Derbyshire*	28	70	680	745	1011
Area 46 - Gloucestershire*	28	124	165	191	259
Area 47 - Herefordshire*	28	65	644	716	972
Area 48 - Leicestershire	28	66	185	224	304
Area 49- Oxfordshire	28	63	383	433	588
Area 50- Shropshire*	28	60	1294	1479	2007
Area 51- Somerset*	28	70	820	885	1201
Area 52- Warwickshire	28	63	819	915	1242
Area 53- Wiltshire	28	70	150	167	226
Area 55- Shropshire*	28	61	82	103	140
Area 56- Hampshire	28	73	206	229	311
Area 57- Berkshire	28	79	67	74	101
Area 58- Staffordshire*	28	98	274	304	413
Area 59- Worcestershire*	28	110	215	239	324
Area 60- Shropshire*	28	70	622	687	932
Area 61- Oxfordshire	28	76	427	474	644
Area 62- Buckinghamshire*	28	137	599	652	885
Area 63- Cornwall	28	122	339	369	500
Area 64- Cornwall	28	122	302	321	435
Area 65- Derbyshire*	28	115	634	685	930
Area 66- Devon*	28	120	165	161	218
Area 67- Hampshire*	28	170	451	490	665
Area 68- Northamptonshire*	28	112	1494	1625	2205
Area 69- Oxfordshire	28	115	250	271	367
Area 70- Somerset*	28	117	127	138	187
Area 71- Warwickshire*	28	103	577	674	914
Area 72- Warwickshire*	28	108	1148	1277	1733

1. Area 54- Lincolnshire did not have minimum and maximum numbers. ↩

2. https://www.gov.uk/government/publications/advice-to-natural-england-on-setting-minimum-and-maximum-numbers-of-badgers-to-be-controlled-in-2022. ↩

3. All first, second, third and fourth year area calculations are based on all historical yearly area data. ↩

4. For Areas listed with ‘*’ the minimum and maximum numbers presented in Table 1 exclude the further increase by 1.5% per operational day. ↩

5. For areas in their first year of control, the minimum effort required was 110.1 units per 100km² per night over 43 days of operations. For areas in their second, third and fourth years of control, required effort was relative to the abundance of badgers reported in the area, with a recommended target of 62.5 units per 100km² per night over 43 days of operations. As some areas choose to continue beyond 43 days to maximise disease control benefits, all areas expended an appropriate level of targeted effort across their control area. ↩