Great Northern Diver
Gavia immer         Common Loon


BOU Category:
Site status
Devon status:
Conservation status:
Conservation levels:
A (GB and site)
uncommon winter visitor and passage migrant, scarce Apr-Oct
uncommon winter visitor and passage migrant to coastal waters; rare inland

BOCC3: amber-listed; non-SPEC3 (Secure); Global IUCN (Least Concern)
nationally important: ≥25 (winter); internationally important: ≥50 (winter)

Nearctic; breeds at deep lakes in N America, Greenland (500 - 2000 pairs) and Iceland (200 - 300 pairs).  Departing Sep/Oct to winter along both Atlantic and Pacific coasts of N America and the coasts of N Europe.  Winters up to 10 km offshore to fish for Herring and Codling, though comes closer during inshore winds, where in shallower waters it also preys on crustaceans, cephalopods and flat-fish

Britain and Ireland support 75% of the Western Palearctic wintering population of c.5400 birds.  It also winters around Iceland (<1000, Norway (<1000) and France (250 - 500); much smaller numbers winter coastally elsewhere.

Great Britain and Ireland
No confirmed breeding records, report from 1970 now suggested a hybrid pair; however small numbers over-summer.   Wintering population split between Ireland, Scotland and the rest of Britain, chiefly along the W coast.  Peak counts in Apr/May in Scotland and SW England attributable to birds returning to breeding grounds from Norway and France, respectively.

Winters Nov - Mar singly or in small groups mostly along the S coast, scarcely along the N coast and rarely on inland reservoirs. Wintering double-figure counts are usually scarce, most often seen in Torbay (max 44 on 22 Dec 1999, associated with 37 two days later off Hope’s Nose).  Excluding Dawlish Warren/Bay, other sites with double-figure maxima include Teignmouth (22 on 30 Jan 2009), Berry Head (14 on 01 Dec 2000), Thurlestone Bay (10 on 11 Jan 2010), Plymouth Sound (10 Jan 1966 & 1979) and Prawle Point (13 on 09 Feb 1980).  A max of 19 in Mar 2005 at Branscombe was followed by 31+ on 13 Apr; these unusually high counts are attributed to birds being temporarily flightless during their pre-breeding moult when primaries are lost simultaneously during the period Feb to Apr.  

Spring passage west through the English Channel is during Apr/May.  The county record of 68+ was off Beer Head on 09 Apr 2010.  Away from Dawlish Warren, double-figure spring passage counts are scarce, achieved at Prawle Point (23+ on 08 May 2004 & 19 May 2007), Berry Head (17 on 13 May 2007) and Torbay (12 in Apr 2009).

It becomes very scarce in Devon from Jun to Sep/Oct and is rare in Jul and Aug.

Dawlish Warren

The earliest site record is, “In 1789, the Northern Diver was shot near Exmouth”.  

Although the bird-days totals over recent decades have increased dramatically - 1980s (251 on 152 dates), 1990s (615 on 368 dates) and 2000s (1620 on 689 dates), its status here is suspected to have changed little since the annual publishing of records, and the increase merely reflects increased reported sightings. 

Single birds account for nearly 60% of all counts (1977 - 2011) and infrequently more than five occur.  Double-figure counts are very scarce, having occurred on only 25 occasions (1.8% of counts) during the same period.


Up to 1998, the first autumn records usually occurred from mid-Oct to mid-Nov, but since the late 2000s, the earliest reports can be from late-Aug/early-Sep, and only sometimes not until late-Oct.  The earliest returning dates are 20 Aug 2011, 21 Aug 2010 and 29 Aug 1992.  Late autumn/early winter passage counts (01 Nov to 15 Dec) have reached double-figures on twelve occasions (1977 - 2011) and the largest recorded counts are 24 on 15 Nov 2009, 25 on 30 Oct 1955 and the site max count of 46 on 06 Dec 2000 - a nationally important count.

Wintering records peak in early-Jan and counts in mid-winter have reached double-figures on only four occasions (1977 - 2011) with maxima since 1938 of 25 on 19 Dec 1954 and 16 on 24 Dec 1961, 02 Jan 2000 and 02 Jan 2001. Wintering records tail off into late-Feb and some passage and lingering wintering birds are recorded through Mar.

Discernible spring passage picks up through late-Apr, peaks in May and curtails promptly in late-May/early-Jun.  Spring counts have reached double-figures on eight occasions (1977 - 2011) with the highest since 1938 being 17 on 02 May 2010, 20 on 22 May 2006 and 22 on 22 May 2002.  Spring passage is predominantly in a SW direction along the coast, although on occasion noted flying inland (see below).

Unseasonal records occur in more years than not and are not a recent phenomenon e.g. one on 09 Aug 1948.  These records can be just single dates, sometimes records span many weeks e.g. 12 May - 06 Jul 1979, 04 Jul - 30 Sep 1990 and was recorded in every month in 1954 and 2000.

03/12/2009 © Simon Thurgood

The record annual bird-days total of 339 in 2000 is three-times higher than the bird-days average (111) for 1990 - 2009. This phenomenon was also reflected in Dorset where, for instance, “exceptional coastal passage was recorded from West Bexington in Dec 2000”, which coincided with the extraordinary site record count.  Also in Dorset, “Record counts also occurred during spring passage at Portland Bill in…2002 (49 birds) [and]…the highest ever count for the spring gathering of moulting birds in Weymouth Bay" .  This coincided with the heaviest recorded spring passage on site (82 bird-days in May 2002).

The majority are seen offshore, fishing or flying by, and in some winters singles, rarely small numbers remain within the estuary.  One was found oiled on the mudflats sometime in 1936 and several were affected by the Napoli spill in Feb 2007.

During spring passage some migrants investigate the estuary, flying around in a large arc to eventually head S back out to sea.  However, individuals or flocks have occasionally flown N at height up the Exe Estuary, presumably to migrate overland e.g. 11 and 9 on 09 & 10 May 2009 (although some may have returned unseen). 

03/12/2009 © Simon Thurgood

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Updated 31/08/2013