Cuckoos travelling to the UK are out of sync with their victims’ nesting clocks due to global warming which is bringing spring earlier. Scientific American reported last year that spring in the UK arrived a month earlier than in the 1980s and that the trend was revealed in 250 years of records. They also state that the trend is generally happening worldwide.
As reported in The Times, it has been discovered that cuckoos face an uncertain future in Britain because their annual migration from Africa is now out of synchronisation with the breeding season of the birds that they fool into rearing their young (a form of parasitism). The breeding season for these birds is earlier than usual.
And the problem is this: the cuckoos cannot leave Africa earlier in order to re-synchronise themselves with the earlier onset of spring in the UK.
Data from 87 cuckoos tagged since 2011 in a research study tells us that cuckoos must remain in West Africa for the explosion in invertebrate numbers brought by the arrival of the spring rains. They need to feed on the invertebrates in order to prepare themselves for the long journey north. If they don’t their chances of survival decrease.
The root cause of the problem therefore is that spring is not coming earlier in West Africa but it is coming earlier in the UK.
“Although the timing of that annual event remains unchanged, spring is arriving earlier in Europe, leading to a potential mismatch between the cuckoos’ arrival, the peak availability of the caterpillars they rely on for food, and the breeding cycles of the species they parasitise” – the British Trust for Ornithology (BTO).
As a result, cuckoos face an uncertain future in Britain unless they find a way to adjust. A 2010 study found that the bird species targeted by the cuckoo, including dunnocks and reed warblers, had shifted their breeding forward by 5-6 days on average. The research was carried out by the BTO.
This is an example of how humankind has negatively impacted in a subtle way the survival of a wild species. There will be many examples of how global warming is going to be very destructive to wildlife.
Intensive farming harms bird life more than climate change and urbanisation
