Merlin

Listen to example recordings of the main vocalisations of Merlin, provided by xeno-canto contributors.

This species can be found on the following statutory and conservation listings and schedules.

UK Birds of Conservation Concern	Red listed
Species of European Conservation Concern	Vulnerable
IUCN Red List of Threatened Species (global)	Least Concern
Schedule 1 license required (to disturb)	Yes
Birds Directive Annex 1	Yes
Listed on the Annexes of	WCA(I,IV), WBD(I), Bern(III), Bonn(II), CITES(II)

Having declined substantially over the past two centuries, Merlin shows indications of a recent doubling of UK population (Rebecca & Bainbridge 1998). Because of its recent population upturn, the species was moved from the red to the amber list in 2002. It remains much too scarce, however, for annual population monitoring via BBS: dedicated observers and specialised field methods are required, as described by Hardey et al. (2009).

A repeat survey of Merlin's British breeding status undertaken in 2008 found a non-significant decline of around 13% since the previous survey in 1993-94, with decline most noticeable in northern England (Ewing et al. 2011). The historical UK decline now warrants red rather than amber listing (Eaton et al. 2015).

Breeding Merlins prefer uplands, especially heather-dominated moorland. They are most abundant on the Scottish islands, in the northern and eastern Highlands of Scotland, the north Pennines and in northwest Ireland. In winter many of these areas are vacated, with Merlins generally preferring low-lying areas in winter, except in Ireland where many of the same breeding areas remain occupied.

Merlins are recorded throughout the year but more obviously so during autumn migration.

View a summary of recoveries in the Online Ringing Report.

Foreign locations of birds ringed or recovered in Britain & Ireland

View number ringed each year in the Online Ringing Report

Maximum Age from Ringing	12 years 8 months 17 days (set in 1989)
Typical Lifespan	3 years with breeding typically at 1 year
Adult Survival	0.62±0.11
Juvenile Survival	0.23 (in first year)

Wing Length	Adults	221.6±12.3 | Range 198–236.5mm, N=20
	Juveniles	218.5±15.4 | Range 204-235mm, N=41

Body Weight	Adults	229±56.3 | Range 148–343g, N=20
	Juveniles	202±34 | Range 144–255g, N=39

Feather measurements and photos on featherbase

Ring size	D (males) E (females)
Field Codes	2-letter: ML | 5-letter code: MERLI | Euring: 3090

For information in another language (where available) click on a linked name

Causes of change

The main causes of change are uncertain.

Further information on causes of change

Recent population increases may be associated with an increased use of forest edge as a nesting habitat (Parr 1994, Little et al. 1995, Rebecca 2011, Lusby et al. 2017). Breeding performance has tended to improve since the 1960s, probably linked to the declining influence of organochlorine pesticides (Crick 1993, Newton 2013). Hatching rates in the southeast Yorkshire Dales were consistently higher than had been recorded in earlier studies in Northumberland (Wright 2005). Submissions to the Rare Breeding Birds Panel fall well short of the estimated UK total population but show an minimum of 1.86 young fledged per occupied territory on average during 1996-2004 (Holling & RBBP 2007a), and a minimum of 1.53 young per territory on average during 2005-2008 (Holling & RBBP 2008, 2009, 2010a, 2010b). Full details of the minimum number of young fledged across all territories reported to the RBBP were not published after 2008, but where data are available productivity can be highly variable between years and particularly across different regions. In 2015, for example, no young fledged from 13 pairs in Meirionnydd and only one from 23 pairs in Northumberland, but 164 young fledged from 50 nests in a Durham study area, giving an overall average of 1.91 fledged young per nest across these three areas (Holling & RBBP 2017). A study in Ireland found that nest success was positively linked to the proportion of foraging habitat close to the nest site (Lusby et al. 2017). On Langholm moor in SW Scotland, Hen Harrier and Merlin numbers increased during periods of grouse moor management and more nesting attempts were successful; this was believed to be due to predator control (Ludwig et al. 2020a).

A decline observed during a thirty year (1984-2014) study in south-east Scotland was attributed to changes in land use management in the breeding area (Heavisides et al. 2017).

Information about conservation actions

The causes of change for this species are unclear and hence further research is needed before evidence-based conservation solutions can be proposed.

In the meantime, actions to maintain and, where appropriate, to restore foraging habitat in breeding areas would be prudent. A study in Ireland found that nest success was positively linked to the proportion of foraging habitat such as moorland, heathland, peat bogs and natural grassland close to the nest site (Lusby et al. 2017). Keepering that remains within the law can also benefit harrier populations by increasing their prey and reducing levels of their nest predators, especially crows and foxes (2020a).