Whilst briding Nada Dairy Farm in Hofuf on 8 April 2016, I heard a
reeling warbler in a large rough fodder field. The bird sounded like a Common
Grasshopper Warbler and not like the more common Savi’s Warbler that also
occurs in the region at this time of year. After some careful looking I saw the
bird perched on a grass stem and then again in flight confirming its
identification. The Common Grasshopper Warbler Locustella naevia is a rare passage migrant to the Eastern Province
and central Saudi Arabia including the Riyadh area. Birds are seen during the
migration season with most in March and April and again in September. I have
seen two previous birds, a single at Dhahran on 1 April 2012 and one in a pivot
irrigation field near Nayriyyah 14 March 2013. I also trapped and ringed a
further one 27 March 2015 at Sabkhat Al Fasl. The subspecies trapped was one of
the western races, either nominate Locustella naevia naevia or Locustella
naevia obscurior due to the wing length of 64 with eastern birds having wing
lengths of less than 60. Locustella naevia naevia breeds in Europe from
southern Scandinavia and southern Finland south to Britain and Ireland,
northwest Iberia, east to western European Russia and Ukraine and winters in
west Africa whilst Locustella naevia obscurior breeds Caucasus mountains south
to northeast Turkey and Armenia with non-breeding birds moving to northeast
Africa. These birds have a darker colour than eastern birds that have a
distinctly paler and more olive-grey ground-colour with L. n. obscurior
differing from nominate naevia by being slightly more olive with heavier,
blacker, and more contrasting spots on upperparts; feather-fringes more olive,
less brown, sandy-grey rather than olive-brown when worn; flank more tinged
rusty-cream (BWP).
