Acrocephalus 22 (104-105): 3 – 9, 2001
1. Introduction
The Yemen Serin Serinus menachensis is a resident
endemic bird with a range restricted to the Endemic
Bird Area (EBA 118) of the south-western Arabian
mountains (Stattersfield et al. 1998). Until 1997
its known distribution was limited to the highlands
of the south-western part of Saudi Arabia north to
21°30´ N and the western part of the Republic of
Yemen east to 47° E. In this area it inhabits dry stony
places with variable amount of vegetation, hillsides
and cliffs with patches of cultivation, but also towns
and villages (Everett 1987, Clement et al. 1993,
Jennings 1995, Porter et al. 1996). 
In October 1997, an isolated population of Yemen
Serin was discovered in the Dhofar region, Sultanate
of Oman, at the Tawi Attair sinkhole 17°06´N /
54°33´E (Polak in print). The record was accepted
as a new breeding species for Oman by the Oman
Bird Group Rarities Committee on 28th February
1998. Thereupon other ornithologists have also
observed adults of Yemen Serin feeding their young
in March and April at the same site.
Little is known about the breeding of the Yemen
Serin and only a few nests have been found so far.
Deetjen (1971) found a nest with eggs inside an unin-
habited building in Sana’a in March 1970; Philips
(1982) found nest(s) in cliff clefts in late September
1982 in Yemen and Cornwallis & Porter (1982)
recorded nests in holes of rock faces and walls in
Description of nests, nestlings and breeding behaviour of a Yemen
Serin Serinus menachensis population in Tawi Attair sinkhole, Sultanate
of Oman
Opis gnezd, mladi~ev in gnezditvenega vedenja populacije jemenskega gril~ka
Serinus menachensis v udornici Tawi Attair, Sultanat Oman
Slavko Polak
Notranjski muzej Postojna, Ljubljanska c. 10, SI-6230 Postojna, Slovenia, e-mail: slavko.polak@guest.arnes.si
The Yemen Serin Serinus menachensis is a resident endemic bird with a range
restricted to the highlands of South-west Arabia. I investigated a recently dis-
covered and isolated breeding colony at Tawi Attair sinkhole in Dhofar,
Sultanate of Oman. Compared to the known breeding sites in western Saudi
Arabia and Yemen, the Dhofar population occurs at a noticeably lower alti-
tude of 680 metres. In this paper, 10 nests found in October 2000 are
described. The nests were colonially grouped in a great rock shelter, mainly
situated beneath an overhang in a rock crevice and in two cases in empty
African Rock Martin Ptyonoprogne fuligula nests. The nests were cups of sticks
and grasses. The inner layer was lined with feathers and animal hairs.
Characteristically dry grasses hung from the coarse nests. A downy nestling
and fully fledged young are described. The nestlings were tended by both
parents. Adults usually perch on rocks near the nests and mainly fly and feed
in flocks at some distance. My findings suggest that Yemen Serins, at the site
investigated, start breeding soon after the end of the monsoon period in late
August and September. Adults show strong colonial behaviour, but the hatch-
ing does not appear to be synchronised.
Key words: Serinus menachensis, Yemen Serin, nest, nestlings, breeding behaviour,
Tawi Attair sinkhole, Sultanate of Oman
Klju~ne besede: Serinus menachensis, jemenski gril~ek, gnezdo, mladi~i, gnezditveno
vedenje, udornica Tawi Attair, Sultanat Oman
3
March and April 1982 in Yemen. The OSME
Expedition (Rands et al. 1987) recorded two breeding
Yemen Serins in October and December 1986, both
using old nests of African Rock Martin Ptyonoprogne
fuligula on a rock face beneath an overhang. Records
on the ABBA database indicate nest building in April
(Saudi Arabia), breeding in March (Yemen highlands)
and food begging juveniles in June (Saudi Arabia). 
2. Methods
This paper is based on personal observations at the
breeding colony of Yemen Serins in Tawi Attair sink-
hole, Dhofar, Sultanate of Oman. Field data were col-
lected between 30 October and 10 November 1997
and 2 to 5 October 2000. Observations were made
in the vicinity of the nests, using a 10 × 25 binocu-
lars and a 32 × 80 telescope from the edge of the sink-
hole. The description of the nests refers to the nests
found in October 2000. The breeding nest sites were
briefly described, the main features of the nests were
estimated without measuring. Among the 10 nests
found, only 2 were directly accessible and could be
measured. Breeding birds and nests were pho-
tographed with 400 mm lenses and flash.
3. Results
3.1. Breeding site description 
The Tawi Attair sinkhole is situated near Tawi Attair
village, east of Salalah on the high karst Samhan
plateau. The area lies within the monsoon belt and is
therefore relatively well vegetated. During and after
the monsoon rains and mists between July and
August, the flat plateau and gentler slopes become
covered by dense tall grasses usually heavily grazed by
cattle (Sale 1980). The steep slopes and wadi sides in
the surrounding area are thickly wooded with trees
and shrubs. The sinkhole (Figure 1) is one of the
largest sinkholes in the world – an imposing 211 m
deep collapse doline with a diameter of 130 m. The
steep sides of the upper part of the sinkhole are dense-
ly wooded. The sinkhole and its cave beneath are
4
S. Polak: Description of nests, nestlings and breeding behaviour of a Yemen Serin Serinus menachensis population in
Tawi Attair sinkhole, Sultanate of Oman
Figure 1: The Tawi Attair sinkhole with marked positions of 10 Yemen Serin Serinus menachensis nest sites found in
October 2000
Slika 1: Udornica Tawi Attair z vrisanimi mesti 10 gnezd jemenskega gril~ka Serinus menachensis, najdenimi oktobra 2000
described in detail by Hanna & Al-Belushi (1996).
The walls and cliffs of the sinkhole are inhabited by
various other breeding birds, notably Tristram’s
Grackle Onychognathus tristramii, Rock Dove Colum-
ba livia, Pallid Swift Apus pallidus and African Rock
Martin Ptyonoprogne fuligula. The known breeding
sites in western Saudi Arabia and Yemen are at a much
greater altitude than the Dhofar population. The low-
est record in those areas is 1950 m, while the Tawi
Attair sinkhole is at an altitude of 680 m. The Tawi
Attair sinkhole is at least 800 km to the east from
known breeding sites of this species in Yemen.
3.2. Nest sites and nest description
In November 1997, we found two nests and in
October 2000 ten nests. They were situated in the
northern and in the eastern faces of the cliffs, approx-
imately 90 to 100 metres below the tip of the sink-
hole (Figure 1). The nests were situated mainly
beneath an overhang in a large rock shelter accessible
by man. Although all the rocks are perforated to a
great extent, the breeding birds were nesting grouped
only in that part of the rock shelter. Nests were
approximately 5 to 15 metres apart. The position of
all the nests found in October 2000 are marked in
Figure 1. In Figure 2, the position and shape of the
nests are shown.
Nest 1: Situated in a rock hole in the middle of the
rock overhang, approximately 5 metres above the floor
of the shelter. The nest was inside the rock hole and
the entrance was 15 × 20 cm in diameter. The only
visible nest material was dry grass hanging from the
hole. Above the hole a deposit of fresh bird droppings
was found. Adult birds frequently visited the nest hole.
Nest 2: Four metres distant from the first one. It was
situated in a rock cavity 20 × 30 cm wide and there-
fore clearly visible. It was placed higher above the
ground and more exposed to the sunlight. Parents
were observed to feed the young (Colour appendix –
Figure 4), and nestlings’ calls were heard.
Nest 3: Also situated in the middle of the overhang
and approximately 7 m above the shelter floor. Placed
in a rock cavity with two entrances. The smaller
entrance was filled with plant material and birds used
the bigger 15 × 30 cm wide hole as the entrance. Two
young were begging for food and tended by both par-
ents. Only 1.5 m from the nest, there was a nest
occupied by an African Rock Martin with fully grown
nestlings.
Nest 4: The only nest directly accessible to me. It
was on the rock wall near to the inner edge of the
rock shelter, 2 m high. The nest was in a rock hole 6
× 8 cm wide and 20 cm deep. Although relatively
deeply situated in the hole, some plant material was
still visible from the outside. I caught a Yemen Serin
female with clearly visible brood patch. After taking
biometric measurements I released it. In the nest
there was a single 4–5 days old downy nestling
described below (see 3.3). The female returned to
the nest a few minutes after I left the site. The nest
was a densely lined cup, with inner diameter of
approximately 5–6 cm. There were no droppings
below the nest hole.
Nest 5: Also on the bigger (20 × 30 cm) rock hole,
built on the outer edge of the shelter about 5 metres
high. It was situated on a small rock ledge and there-
fore clearly visible. It was made of dry grass. At this
nest I did not record visits of adult birds, but drop-
pings found below clearly showed that the nest had
been used recently. From the fresh droppings I inferred
that the nestlings had recently left the nest.
Nest 6: Built in an old African Rock Martin’s nest
hanging on the rock wall in the middle of the rock
shelter. I observed adults sitting on the nest many
times. Long grasses were clearly visible hanging from
the nest. When I approached the site, the adults were
disturbed and flew away, but returned soon after. The
lack of droppings below the nest suggested that there
were eggs or young nestlings in it.
Nest 7: This nest lies also in an old African Rock
Martin’s nest (Colour appendix – Figure 1). Grass was
not so visible as in nest No. 6. The adults were visit-
ing the nest frequently and begging by fully grown
nestlings was heard. Whenever the nest was
approached, the adults became nervous. They did not
fly away but remained close nearby. On 4 October
this nest was examined with an aid of a metal ladder.
It contained 3 fully grown nestlings, described later
(see 3.3.). The nest was a cup of grasses, sticks and
roots. The outer coarse cup was irregular and adapt-
ed to the shape of the Martin’s nest and the sur-
rounded rock. The inner cup was dense, 5–6 cm in a
diameter and made of fine dry grasses and lined with
plant down, hairs and feathers. The hairs were of dif-
ferent mammal species, probably of cattle, goats and
a carnivore. The feathers were mainly down and
coverts of Rock Doves and Tristram’s Grackles. Under
the nest, a deposit of fresh bird droppings was accu-
mulating.
5
Acrocephalus 22 (104-105): 3 – 9, 2001
6
S. Polak: Description of nests, nestlings and breeding behaviour of a Yemen Serin Serinus menachensis population in
Tawi Attair sinkhole, Sultanate of Oman
Figure 2: The position and shape of the 10 Yemen Serin Serinus menachensis nests in the Tawi Attair sinkhole rock shelter
found in October 2000
Slika 2: Pozicije in oblike 10 gnezd jemenskega gril~ka Serinus menachensis, najdenih oktobra 2000 pod skalnim previsom
v udornici Tawi Attair
Nest 8: This inaccessible nest was situated on the
outer edge of the shelter roof. We only saw the gras-
ses hanging down from the rock hole measuring
30–40 cm in diameter. 
Nests 9 and 10: Situated in part of the rock shelter
where the roof of overhang was 7 to 10 metres high,
but could not be closely investigated due to the dan-
ger of slipping into the sinkhole. Under the roof of
the rock shelter there were plenty of rock holes and
crevices. In two places I observed adults visiting
holes, one with 15 × 15 cm (nest No. 9) and one with
30 × 40 cm (nest No. 10) in diameter, from where
grasses as nesting material were seen. 
3.3. Description of nestlings and fledglings
At nest No. 4, I found one altricial and downy nestling
(Colour appendix – Figure 2). According to the figures
of stages in growth of an altricial nestling (in the case
of sparrows) (Harrison 1988) I estimated that the
nestling was approximately 4–6 days old. It was still
blind and naked, but the plentiful, dense and rather
long silver-grey down was confined to the head, from
the shoulders it extended along the back, as well as to
the bases of wings and legs. The feathers of the wings
and the tail had not yet appeared (Colour appendix –
Figure 2). On the underside there was no down. The
rounded pale and black seeds of approximately 1 to 2
mm in diameter were clearly seen through the trans-
parent skin of the gut. No insect remains were detect-
ed in the gut. The mouth of the chick was yellowish
white with pink tongue and pink-red palate. The pale
yellow gape flanges were noticeable.
In nest No. 7, 3 fully grown nestlings were ready to
leave the nest. During the examination of the nest,
one nestling left the nest. It was not able to fly
properly but was agile enough to prevent me from
catching it once more. There were few other flying
young observed around the site. Fully fledged young
are similar in colour to the adults, but noticeably
duller (Figure 3). The brown streaks on the
underparts and breast are more visible than those of
adults. Tail feathers are much shorter. The young can
be also distinguished from the adults by the
noticeably yellow coloured bill and the pale white
gape flanges. 
3.4. Breeding behaviour
My observations of the breeding colony of Yemen
Serins indicate strong colonial behaviour. The adult
birds usually gathered in flocks of 5 to 10 birds.
They normally gathered for some time at the breed-
ing site and then left the site as a flock. When the
flock returned the pairs tended the young separately.
They perched near nests mainly on the rock on a
higher position and occasionally on a small bush at
the edge of the shelter. The ground dwelling behav-
iour was also observed especially in the case when
the adults fed the recently fledged birds. At dusk one
of the parents sat on the nest, whereas the other
perched on the nearby rock hole. The adults used to
communicate continuously by repeated characteris-
tic calls. Adults were not observed feeding in the
vicinity of the breeding site, but drinking water from
the cave stalactites was seen during my visit in 1997
and 2000.
Aggressive behaviour towards other species was not
noticed. African Rock Martins occasionally demon-
strated flight attacks against Serins. Competition for
the empty African Rock Martins’ nests is the most
likely reason.
My findings suggest that this colony of Yemen
Serins begins to breed soon after the end of the mon-
soon period in late August and September. Despite
the colonial behaviour of the species, the start of
breeding does not seem to be synchronised. As for
example some nests have nestlings and probably eggs
whilst fully fledged young have already left the nest.
Acknowledgement: I would like to thank Lara Jogan
Polak and Siegfried Huber for assisting me during my
field work. The help of Faraj Omar Bakeet, the tech-
nician of the local Tawi Attair hospital, who provided
me with the metal ladder, was crucial for the investi-
gation of the nests situated beneath the overhangs.
7
Acrocephalus 22 (104-105): 3 – 9, 2001
Figure 3: Fully fledged nestling of Yemen Serin Serinus
menachensis, Tawi Attair sinkhole, 4 October 2000
Slika 3: Operjeni mladi~ – poletenec jemenskega gril~ka
Serinus menachensis, udornica Tawi Attair, 4. oktober 2000
Our last expedition to the Sultanate of Oman was
possible with the support of Prof. Dr. Peter Weygoldt
(Freiburg University). I would like to express my grat-
itude to Ali bin Amer al Kiyumi, Director-General of
Nature Conservation (Ministry of Regional Munici-
palities & Environment of Sultanate of Oman) for
giving us official permission for biological field work
and Ian Harrisons (Oman Bird Group) for the logis-
tic support. I extend my sincere thanks to Michael
Jennings (Co-ordinator of Atlas of the Breeding Birds
of Arabia) for his constructive suggestions and cor-
rections.
4. Povzetek 
Jemenski gril~ek Serinus menachensis je endemi~na
vrsta ptice z arealom, omejenim na visokogorje J-Z
dela Arabskega polotoka. Pred kratkim je bila odkrita
nova kolonija te vrste v udornici Tawi Attair v
provinci Dhofar v Sultanatu Oman. Avtor v ~lanku
opisuje obmo~je novega gnezdi{~a Tawi Attair in
podrobneje 10 gnezd, najdenih oktobra 2000.
Namen ~lanka je osvetliti poznavanje gnezditvene
biologije te endemi~ne vrste ptice, o kateri je doslej le
malo znanega. Obravanavano gnezdi{~e je 800 km
vzhodneje od doslej znanih v Republiki Jemen in v
Savdski Arabiji, kjer so gnezdi{~a na znatno vi{jih
nadmorskih vi{inah. Kolonijsko grupirana gnezda v
velikem skalnem spodmolu so bila name{~ena
ve~inoma v skalnih luknjah in {pranjah pod stropom
previsa. Dve gnezdi sta bili narejeni v praznem
gnezdu afri{ke skalne lastovke Ptyonoprogne fuligula.
Gnezda so skledaste oblike, izdelana iz pali~ic in
predvsem suhe trave, ki zna~ilno visi iz gnezdilnih
lukenj. Notranji del gnezda je postlan s perjem in
dlako. V ~lanku so prvi~ opisani 4–6 dni star puhasti
mladi~ in mladi~i, ki so `e poleteli iz gnezd. Mladi~e
hranita oba star{a. Avtor sklepa, da populacija
jemenskih gril~kov v Omanu pri~ne gnezditi po
monsunskem obdobju konec avgusta in septembra.
Kljub izra`enemu kolonijskemu vedenju pri tej vrsti
pa je videti, da izvalitev mladi~ev ni sinhronizirana.
5. References
Clement, P., A. Harris & J. Davis (1993): Finches &
Sparrows. An Identification Guide. Christopher Helm,
A & C Black, London.
Cornwallis, L. & R.F. Porter (1982): Spring Observations
on the Birds of North Yemen. Sandgrouse 4: 1-36.
Deetjen, H. (1971): Ornithological notes from Yemen.
Alauda 39 (1): 43-53.
Everett, M.J. (1987): The Arabian and Yemen Serins in
North Yemen. Sandgrouse 9: 102-105.
Hanna S. & M. Al-Belushi (1996): Introduction to the
Caves of Oman. Sultan Qaboos University, Sultanate of
Oman. 
Harrison C. (1988): A field guide to the Nests, Eggs and
Nestlings of European birds with North Africa and the
Middle East. Collins Ltd., London. 
Jennings, M.C. (1995): An Interim Atlas of the Breeding
Birds of Arabia. National Commission for Wildlife
Conservation and Development. Saudi Arabia.
Phillips, N. R. (1982): Observations on the Birds of
Northern Yemen in 1979. Sandgrouse 4: 37-59.
Polak, S. (in print): The first record of Yemen Serin Serinus
menachensis in Oman. Oman Bird News 22. Oman Bird
Records Committee, Sultanate of Oman.
Porter, R.F., S. Christensen & P. Schiermacker-
Hansen (1996): Field Guide to the Birds of the Middle
East. T & AD Polyser Ltd, London.
Rands, M.R.W., R.F. Porter, D.J. Brooks & G.F. Rands
(1987): The Ornithological Society of the Middle East’s
Expedition to North Yemen October–December 1986.
Introduction. Sandgrouse 9: 1-3.
Sale, J. B. (1980): The Environment of the Mountain
Region of Dhofar. In: The Scientific Results of the
Oman Flora and Fauna Survey 1977. Journal of Oman
Studies, Special report No .2. 17-25.
Stattersfield, A.J., M.J. Crosby, A.J. Long & D.C.
Wege (1998): Endemic Bird Areas of the World:
Priorities for Biodiversity Conservation. BirdLife
Conservation Series No. 7. BirdLife International,
Cambridge. 
Arrived / Prispelo: 24.4.2001
Accepted / Sprejeto: 15.6.2001
8
S. Polak: Description of nests, nestlings and breeding behaviour of a Yemen Serin Serinus menachensis population in
Tawi Attair sinkhole, Sultanate of Oman