The slender-billed gull (Chroicocephalus genei) belongs to the family of gulls, terns and skimmers, Laridae.
The slender-billed gull species are distributed in India, Pakistan, Afghanistan, Middle East, southern Europe, central Asia, northwest Africa and Mediterranean region. These gull species are partially migratory. These gulls are monotypic species.
Slender-billed gull - Overview
- Scientific name: Chroicocephalus genei
- Species author: (Breme, 1839)
- Synonyms/Protonym: Larus Geneï Brème, 1839
- Family: Laridae › Charadriiformes › Aves › Chordata › Animalia
- Vernacular names: English: Slender-billed gull, Chinese: 细嘴鸥, French: Goéland railleur, German: Dünnschnabelmöwe, Spanish: Gaviota picofina, Russian: Морской голубок, Japanese: ハシボソカモメ, Arabic: النورس مستقيم المنقار
- Other names: Rosy Gull
- Distribution: India, Pakistan, Afghanistan, Middle East, southern Europe, central Asia, northwest Africa, Mediterranean region
- Diet and feeding habits: small fish, insects, aquatic invertebrates
- IUCN status listing: Least Concern (LC)
Appearance, physical description and identification
The slender-billed gull (Chroicocephalus genei) is a medium-sized gull, measuring 40 to 45 cm in length and weighing 220 to 350 grams. The wingspan is 100 to 110 cm. Both the sexes look alike.The summer breeding adult slender-billed gull has white head, neck and breast. The upperparts a very pale gray. The lower rump and tail are white. The underparts are whitish.
The primary wing feathers of slender-billed gull have black tip. It has a long sloping forehead. The bill is long thin and deep red in color. The legs are long and reddish. The breast and belly have pink hue. The irises are yellow.
In the wintering adult gull the head shows a small gray spot on the rear ear-coverts. The bare parts like the bill and legs get duller and appear dull orange. The immature birds have a pale gray head, a dark terminal band on the tail and patches on the wing.
The slender-billed gull call is a sharp “ka..ka..ka” and "kra..kra..kra" sound.
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| 1.Birds of India - Image of Slender-billed gull - Chroicocephalus genei by Dhaval Vargiya |
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| 2.Indian birds - Picture of Slender-billed gull - Chroicocephalus genei by Nanosanchez |
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| 3.Birds of India - Photo of Slender-billed gull - Chroicocephalus genei by Nanosanchez |
Origin, geographical range and distribution
The slender-billed gull species are distributed in southern Europe, northwest Africa, central Asia, Middle East, Afghanistan, Pakistan and India.Vagrant slender-billed gulls have been observed in Portugal, United Kingdom, Gibraltar (UK), Germany, Switzerland, Poland, Slovenia, Serbia, Montenegro, Belarus, South Africa, Kenya, Nigeria, Djibouti, Sri Lanka, Nepal, Thailand, Japan, Hong Kong (China), Antigua and Barbuda.
The breeding populations of slender-billed gull are distributed in Pakistan, Afghanistan, Iran, Turkmenistan, Kazakhstan, southwestern Russia, Azerbaijan, Turkey, Greece, Ukraine, Italy, France, Spain and Tunisia.
The wintering slender-billed gull populations are found in India, Pakistan, Iran, Iraq, Saudi Arabia, Unite Arab Emirates, Kuwait, Qatar, Oman, Yemen, Israel, Jordan, Lebanon, Syria, Cyprus, Turkey, Georgia, Ukraine, Azerbaijan, Romania, Greece, Italy, France and Spain.
In Africa the wintering slender-billed gull populations are found Djibouti, Eritrea, Sudan, Egypt, Libya, Tunisia, Algeria, Morocco, Mauritania, Senegal, Gambia, Guinea and Guinea-Bissau.
In India, the wintering slender-billed gull populations are distributed in the states of Gujarat, Maharashtra, Goa and Karnataka.
The Important Bird and Biodiversity Areas (IBA) of the slender-billed gull species in Egypt are Bitter Lakes, El Malaha, Zaranik Protected Area, Lake Qarun Protected Area and Lake Manzala. The IBA in Azerbaijan are Pirsagat Islands and Los Island.
The IBA of slender-billed gull species in Iran are Bahu Kalat Protected Area, Lake Bakhtegan, Lake Tashk, Kamjan marshes, Shadegan marshes, tidal mudflats of Khor-al Amaya and Khor Musa, Miankaleh Peninsula, Gorgan Bay and Lake Uromiyeh.
The IBA of slender-billed gull species in Spain are Albufera de Valencia marshes, Bahía de Almería, Wetlands of western Almería, Santa Pola salt-pans, Plataforma Marina del Delta del Ebro - Columbretes, Guadalquivir marshes, Ebro delta and Mata and Torrevieja lagoons.
The IBA of slender-billed gull species in Russia are Yeiski salt-lakes, Utrish Reserve, Taman', Kozinka lake, Kiziltash limans, Khanskoye Lake, Delta of the River Don, Islands in the western part of Lake Manych-Gudilo and Beglitskaya sand-spit.
Ecosystem and habitat
These slender-billed gull species do not normally occur in forests. These species normally occur in altitudes from 0 to 100 meters.The artificial ecosystems of these gull species include salt pan reservoirs, marine aquaculture ponds, brackish water ponds and coastal freshwater fish culture ponds.
The natural ecosystems of these slender-billed gull species include marine lagoons, brackish water lakes, coastal freshwater lakes, sea cliffs, offshore islands, sandy, rocky, pebble and shingle shorelines, tidal pools, estuaries, shallow seas with submerged microalgae, marshes and swamps.
Diet and feeding behavior
The diet of the slender-billed gull consists mainly of fish. Insects, fish and marine invertebrates are their primary food. The feeding sites include deltas, marshes, water bodies and grasslands.These gulls fly a few feet above the surface of water and on spotting a prey, dive into the waters and catch the prey with bill. The mud is probed with bill for invertebrates. They also hawk the flying insects in air.
Reproduction and breeding habits
The breeding season of these slender-billed gull species in most of its northern range is from March to May. These birds breed in dense colonies of ten to thousands of pairs. The colonies may be of monospecies or mixed-species.The nesting sites of slender-billed gull include coasts of land-locked seas, sand-spits, beaches, banks of water bodies, islands, mudflats and marshes, banks of shallow tidal pools, margins of saline inland seas and margins of steppe lakes.
The slender-billed gull nest is a deep ground scrape or a natural depression. It may be lined with feathers and vegetation. The typical clutch usually contains three spotted, pale buff eggs. Both the parents incubate the eggs for nearly 25 days and hatchlings fledge in four weeks.
Migration and movement patterns
The slender-billed gull species are partially migrant birds.The slender-billed gull populations in central Asia are fully migratory. They leave the breeding grounds in July, migrating to the wintering grounds. The mature birds return to breeding sites in late-February and March. The immature birds may stay back in the wintering grounds.
The slender-billed gull populations in west Africa, Iberian peninsula, Middle East, Persian Gulf, Pakistan and India may migrate for short distances or remain sedentary in the breeding sites.
Post breeding, the juvenile gulls may disperse and establish in new locations within the range. They may make local movements for feeding and breeding within their range.
Conservation and survival
The global population size of the slender-billed gull (Chroicocephalus genei) is estimated at 280,000 to 350,000 individual birds. The overall population trend of these gull species is unknown.Throughout its range this gull species is reported to be locally common. The generation length is 10.5 years. Its distribution size is about 26,000,000 sq.km.
Hunting pressure, tourism pressure, egg collection, predation of eggs and chicks, oil pollution, habitat loss and degradation and susceptibility to avian influenza are the main threats that may endanger the survival of these gull species.
IUCN and CITES status
The slender-billed gull (Chroicocephalus genei) does not approach the thresholds for being Vulnerable, either under the range size criterion, or under the population trend criterion or under the population size criterion.The IUCN (International Union for Conservation of Nature) has categorized and evaluated the gull species and has listed it as of "Least Concern". The CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) status is ‘Not Evaluated’ for slender-billed gull (Chroicocephalus genei).
| Taxonomy and scientific classification of Chroicocephalus genei | |
|---|---|
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Laridae |
| Subfamily: | - |
| Genus: | Chroicocephalus |
| Species: | C. genei |
| Binomial name: | Chroicocephalus genei |
| IUCN status listing: |
 Least Concern |
1.Slender-billed gull photo source: https://en.wikipedia.org/wiki/File:Breeding_plumage.jpg (cropped)
Photo author: Dhaval Vargiya | License: CC BY-SA 4.0
2.Photo source: https://commons.wikimedia.org/wiki/File:Larus_genei0243.jpg (cropped)
Photo author: Nanosanchez | License: CC BY-SA 4.0
3.Photo source: https://commons.wikimedia.org/wiki/File:Larus_genei1150240.jpg (cropped)
Photo author: Nanosanchez | License: CC BY-SA 4.0
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