The increase in the Corncrake Crex crex population of the United Kingdom has slowed

Figures & data

Table 1. Numbers of singing Corncrakes recorded in surveys conducted in the UK and the Isle of Man between 1978/79 and 2014. Years with full survey coverage of Great Britain, the Isle of Man or Northern Ireland are shaded grey. Scottish islands included in the core areas counted in every year since 1993 are marked with asterisks.

Area	1978/79	1988	1993	1998	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014
Shetland	3–5	1	3	4	4	2	–	–	1	2	3	–	–	–	–	–
Orkney*	102–105	29–36	6	13	31	17	13	17	21	20	17	27	28	32	12	36
Lewis*	31–38^a	66–76	106	77	105	118	113	101	111	68	81	106	180	141	75	140
Harris*	7	5	4	3	11	24	10	14	12	8	2	2	12	12	4	10
Berneray*	5	1–2	2	2	1	3	3	4	7	7	6	6	6	6	3	3
North Uist*	75	56–59	66	73	77	112	104	100	117	102	93	107	113	131	80	120
Benbecula*	33	22–23	17	41	30	35	28	26	27	25	18	22	14	13	10	31
South Uist*	83	91–100	50	65	101	119	103	110	105	92	90	92	84	113	75	88
Barra, Vatersay & Sandray*	26–28^a	59	26	47	68	72	66	75	76	70	76	80	80	98	68	103
Pabbay, Mingulay & Berneray	–	–	0	0	2	5	3	–	2	2	1	–	4	–	6	4
Skye*	31–34	26–28	8	12	23	32	27	16	18	12	7	25	19	31	38	38
Canna*	9	1–2	3	2	4	4	1	2	3	5	4	0	5	0	0	0
Rum	1–2	0	1	0	0	0	–	–	–	–	0	–	–	–	–	–
Eigg	4–6	0	1	0	0	1	1	–	2	–	0	–	–	–	–	–
Muck	4	0	1	0	5	3	4	3	3	–	0	1	–	–	–	–
Coll*	28	20	20	40	90	134	159	171	180	118	122	116	121	103	64	91
Tiree*	85	99–103	111	136	184	260	310	316	391	408	389	391	385	371	348	396
Mull & Staffa*	1	2–3	1	2	0	5	7	7	5	9	2	8	6	4	4	4
Iona*	25^b	3	4	12	24	24	29	39	30	50	46	34	24	31	25	28
Treshnish Isles & Lunga	1	0	2	3	2	4	3	1	2	2	2	1	1	2	1	2
Colonsay & Oronsay*	22	17–18	10	14	32	46	50	58	71	67	62	72	58	71	53	86
Islay*	22–24	19	9	4	10	31	52	55	66	82	84	81	83	86	87	98
Jura	1	1	0	0	0	0	–	–	–	–	0	–	–	–	–	–
Gigha	1	4	0	0	1	0	–	–	–	–	1	–	1	–	–	–
MacCormaig Islands	0	0	1	0	0	0	1	2	3	2	3	–	2	–	–	–
Scottish mainland	94–103	24–29	18	24	17	12	16	16	24	19	21	23	16	8	11	11
England	11–17	4	8	13	2	1	3	5	8	16	34	21	14	6	8	27
Wales	1	0	1	2	0	–	1	–	–	–	0	–	–	–	–	–
Isle of Man	0–3	1	1	0	6	–	2	1	1	–	0	–	–	–	–	–
Northern Ireland	169^c	122–133^d	9^e	–	–	1	5	1	2	4	2	–	6	1	–	–
Scotland core areas total	585–602	516–556	443	543	791	1036	1075	1111	1240	1143	1099	1169	1218	1243	946	1272
GB total	706–743	550–595	479	589	824	1064	1107	1138	1285	1186	1164	1215	1256	1259	972	1316
UK total	875–912	672–708	488	589	824	1065	1112	1139	1287	1190	1166	1215	1262	1260	972	1316
Grand total	875–915	673–729	489	589	830	1065	1114	1140	1288	1190	1166	1215	1262	1260	972	1316

^aSurveys in this year known to be incomplete.

^bNo survey in 1978–79 so 1977 survey used.

^cData for 1978 from O'Meara (1979).

^dData from Mayes & Stowe (1989).

^eData from Sheppard & Green (1994).

Table 2. Numbers of male Corncrakes captured and located in intensive searches in May in the Arileod – Totronald area of the Isle of Coll, compared with numbers of singing birds in a later standard census of the same area.

Year	Captured	Not captured	Total	Search period	Census	Census period	Change %
2012	50	5	55	19–27 May	67	5–27 June	+22
2013	46	20	66	11–25 May	44	1–20 June	–33
2014	40	12	52	24–31 May	58	3–30 June	+12

Figure 1. The number of singing male Corncrakes in Great Britain between 1978/79 and 2014. The bars show the number of Corncrakes recorded in the full survey years, while the crosses show the numbers recorded in the core range. Filled circles show the annual spring mean temperature (March–May) in North Scotland (Meteorological Office 2015). Counts in 1978/79 on Barra and Lewis were incomplete, so estimates for those islands were imputed by multiplying the count in 1988 by the ratio of the 1978/79 to the 1988 counts for the other islands of the Outer Hebrides, excluding Barra and Lewis (O'Brien et al. 2006). Where upper and lower limits were given for a count (see Table 1), their average was used.

Figure 2. Annual estimates of the rate of growth of the Corncrake population of the Scottish core areas between pairs of successive years in the period 1993 and 2014 in relation to the mean spring temperature (March–May) in North Scotland in the second year of each pair.

Figure 3. Numbers of 1-km (filled symbols) and 10-km (open symbols) Ordnance Survey grid squares with singing Corncrakes in national surveys of Great Britain and the Isle of Man (triangles) and annual surveys of core areas of Scotland (circles), from 1988 to 2014.

Figure 4. Corncrake distribution by 10-km square in Scotland during the full survey years of (a) 1988 (88 10-km squares), (b) 1993 (74 10-km squares), (c) 1998 (79 10-km squares), (d) 2003 (76 10-km squares) and (e) 2009 (84 10-km squares).

Table 3. Numbers of 10-km grid squares with Corncrakes in three BTO Breeding Bird Atlas periods (A1–A3).

	1968–72 Atlas 1	1988–91 Atlas 2	2007–11 Atlas 3	% change A1–A2	% change A1–A3	% change A2–A3
Great Britain	660	161	184	–75.6	–72.1	+14.2
England	193	16	16	–91.7	–91.7	0
Scotland	399	142	166	–64.4	–58.4	+16.9
Wales	55	1	1	–98.2	–98.2	0
Northern Ireland	126	37	15	–70.6	–88.1	–59.5
UK	786	198	199	–74.8	–74.7	+0.5
Isle of Man	13	2	1	–84.6	–92.3	–50.0

O'Meara, M. 1979. Distribution and numbers of Corncrakes in Ireland in 1978. Irish Birds 1: 381–405.

 Google Scholar

Mayes, E. & Stowe, T.J. 1989. The status and distribution of the Corncrake in Ireland, 1988. Irish Birds 4: 1–12.

 Google Scholar

Sheppard, R. & Green, R.E. 1994. Status of the Corncrake in Ireland in 1993. Irish Birds 5: 125–138.

 Google Scholar

O'Brien, M., Green, R.E. & Wilson, J. 2006. Partial recovery of the population of Corncrakes Crex crex in Britain, 1993–2004. Bird Study 53: 213–224. doi: 10.1080/00063650609461436

 Web of Science ®Google Scholar