A History of Birdwatching in 100 Objects

It is alleged that more than 600 species are mentioned in the works of Shakespeare, and Eugene Shieffelin had the ill-conceived idea of trying to introduce them all to North America in the late 19th century; fortunately he failed, but not before House Sparrow and Starling had increased to plague numbers in some areas.

In Sur la Naturalisation des Animaux Utiles – aka On the Naturalisation of Useful Animals (1849) – groundbreaking French biologist Isidore Geoffroy Saint-Hilaire produced copious convincing economic and proto-ecological arguments for the French government to introduce potentially beneficial animals and plants from the newly discovered and exploited colonies, mostly to control agricultural pests and provide different kinds of meat. He then founded the Société Zoologique d’Acclimatation (1854) to promote these ideas.

Saint-Hilaire’s robust evangelising soon influenced the formation of other similar societies across the western world, including in 1871 the American Acclimatization Society (AAS), which had the expressed goal of introducing “useful or interesting” animals and plants to North America, and proceeded to promote itself with some zeal. By 1877 it had attempted to introduce Skylark, Common Starling, Pheasant and Japanese Grosbeak into Central Park, New York City. This wasn’t the first such attempt at introductions – House Sparrows had already become possibly the commonest bird in the city, after eight pairs were freed in Brooklyn in 1851 – but they were the most ideologically driven, persistent and pernicious release of alien species.

The AAS’s chairman in 1877 was a local pharmacist named Eugene Schieffelin, an amateur Shakespeare scholar who is suspected to have been behind the possibly apocryphal idea that every species of bird mentioned in the complete works of the Bard should be introduced to the United States of America – an alleged 600 or more of them. Most of the society’s introductions didn’t take, but both House Sparrow and Common Starling mirrored the progress of colonising settlers, spreading from New York to western Canada, California and Florida by the 1950s. The sparrow population peaked at more than 150 million in the 1950s, but is now in decline, while the starling population – after Schiefflin initially released the species in 1890 (hence the year of inclusion of this older work here) – has topped 200 million this century.

The damage done by these two species is only partially known, as the naïveté that led to the introductions in the first place was also reflected in the lack of information about native North American species available for comparison with modern data. However, they are both known to be agricultural pests, and Common Starling has certainly competed with Yellow-bellied Sapsucker for nest holes. Still, the influence of most European species appears to have been absorbed by the native American avifauna, as it had already robustly evolved to suit a temperate continental biota and climate, like its European rivals.

Where introduced species really do damage is on islands, which have frequently evolved entire radiations of birds, isolated and free from competition. The mid-Pacific state of Hawai’i has lost dozens of unique bird species since being colonised by Polynesians over 1,000 years ago, and even more after Europeans settled. Modern visitors to the archipelago could be forgiven for thinking they had walked into the world’s largest aviary: Java Sparrows from South-East Asia, Yellow-fronted Canaries from East Africa and Black Francolins from the Middle East can all be seen.

Those Hawaiian honeycreepers – a very varied finch radiation – that have not become extinct have mostly been forced into the uplands by loss of habitat and cagebird-derived avian pox. Even there, they share their rainforest with Japanese White-eyes and Mariana Swiftlets from the south-west Pacific.

Birders and ornithologists – usually keen to see or study ‘pure’ wild species – cope with these introductions by categorising them as escapes, exotics or self-sustaining populations. Even species in this last category are frequently reliant on continued reintroductions (probably the case with Pheasant in Britain) or the proximity of humans, or they exponentially expand their populations until they run out of food or habitat – the west Asian Varied Tit performed this boom-and-bust feat following its introduction on Hawai’i. In fact, it is entirely possible to enjoy such introductions as wild birds adapting and changing as nature always does, while being aware of their potentially destructive influence, and they are also valid study subjects to assess how evolution copes with an alien presence.