| Silver gull | |
|---|---|
 | |
| AdultC. n. novaehollandiae, Tasmania | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Laridae |
| Genus: | Chroicocephalus |
| Species: | C. novaehollandiae |
| Binomial name | |
| Chroicocephalus novaehollandiae (Stephens, 1826) | |
| Subspecies | |
C. n. forsteri(Mathews, 1912) | |
Thesilver gull (Chroicocephalus novaehollandiae) is a gull inOceania. It is the most commongull ofAustralia. It has been found throughout the continent, but particularly at or near coastal areas. It is smaller than thePacific gull (Larus pacificus), which also lives in Australia.
The silver gull should not be confused with theherring gull, which is called "silver gull" in many other languages (scientific nameLarus argentatus,GermanSilbermöwe,FrenchGoéland argenté,Dutchzilvermeeuw), but is a much larger, robust gull with no overlap in range.
It has traditionally been placed in thegenusLarus, as is the case with many gulls, but is now placed in the genusChroicocephalus.Hartlaub's gull (C. hartlaubii) ofSouth Africa was formerly sometimes considered to besubspecies of the silver gull.[2]
There are three subspecies:[3]
The head, body, and tail of an adult silver gull are white, and the wings are light grey with white-spotted, black tips.[4] Adults range from 40–45 cm (15.5–17.5 in) in length.[4] Their wingspan ranges from 27 to 31 cm (10.5 to 12 in).[5] Adults have bright red beaks which gets brighter during breeding or when they get older.[6][5]
Juveniles have brown patterns on their wings, and a dark beak.[5][7]
Silver gulls are found in all states of Australia,[6] as well asNew Zealand andNew Caledonia.[4] It is a common species near human habitations and beaches, having adapted well to urban environments and thriving around shopping centres and garbage dumps. Their successful adaption to urban habitats have seen their population increase in areas of human activity, with the availability of nesting grounds the only limiting factor on population growth.[4]
Silver gulls have twice been recorded in theUnited States; one bird was shot in August 1947 at the mouth of theGenesee River,Lake Ontario, and another was photographed inSalem County, New Jersey, in autumn 1996. Both are believed to have escaped from captivity.[8]
The silver gull has a sharp voice consisting of a variety of calls. The most common call is a harsh, high pitched 'kwarwh'.[4]
The silver gull naturally feeds on worms, fish, insects and crustaceans. It is a successful scavenger, allowing increased numbers near human settlements. It is known to pester humans for scraps and steal unattended food.[4]
Breeding occurs from August to December, typically in large colonies on offshore islands.[6] The nest is located on the ground and consists of seaweed, roots, and plant stems.[6] The nests may be found in low shrubs, rocks and jetties.[6] Typical clutch size is one to three eggs.[4][6] Often two broods are raised in a year, and both adults share nest-building, incubation and feeding.[4]
