Wildwestbirds: Large Gulls

The evolution of large Gulls

The Larus group of gulls comprising 21 species is distributed worldwide with many in Europe. The most prominent birds in my location (currently England) is the Herring Gull Larus argentatus. Over the last few decades, science has taken a continuing review of this bird and others comparing differences and similarities in universities, in the lab, and under the microscope resulting in separation, producing new and compelling species. Emerging is that species do indeed form and follow a line keeping them apart due to the natural line breeding mechanism caused by their innate behaviour or geographical separation. This is constantly trimmed and honed by natural selection. Captivating is that species do split into subspecies and geographical variations that will reproduce when confronted with the nominate specie. In recent times we have newly described: Yellow-legged Gull; Caspian Gull which were previously subspecies.

The Cornell Lab of Ornithology, the leading entity for the study of birds around the world, currently reports the status on this difficult subject as follows:

Taxonomy of present species and its close relatives represent one of the most complex challenges in systematic ornithology. The closely related taxa were often treated as a ring of subtle races until the two extremes (L. argentatus, L. fuscus) met in W Europe and did not freely interbreed. Many forms are now treated as separate species, since it is uncertain how to apply the biological or indeed phylogenetic species concept to the complex pattern of variation and interbreeding. Even after several decades of molecular study, uncertainty over the species boundaries of L. argentatus, L. cachinnans and L. fuscus prevails, with many of the identifiable races assigned at one time or another to two or even three of these species.

See also L. fuscus, L. armenicus, L. cachinnans.

Many of these birds are present in the study area of Eastbourne UK

The commonest species present in the study are of Eastbourne UK is the Herring Gull. The Greater Black-backed Gull is also well represented followed by Lesser Black Gull. The superficial features are easy to differentiate. Science is constantly looking for ways to split and identify new species. Often via molecular and laboratory work.

Personally, I have concluded that the human condition leads us to need to order things and create method to conclude that we have distinct and separate species following our discovery. Animals seem to constantly disprove our theories, by not following our perceived lines of evolution and procreating with closely related species and hybridizing which would suggest that they are even closer. These tangents form lines backwards, indicating there is no straight lineage in evolution, but a complex biological soup.