By contributing to global warming, humans are causing major disruptions to birdlife in Portugal and all over the rest of Europe as well as Africa.
For one thing, the annual northward bird migration between Africa and Europe, which traditionally starts this month, is being impacted. Migrants are arriving earlier, staying longer, and in some cases not returning south.
Ornithological studies show that the imbalance has been rapidly increasing and will continue to do so as the planet warms up.
Normally, more than two billion birds have been flying epic journeys from sub-Saharan and southern Africa in spring, and back again in autumn, a total of anywhere between eight and more than twenty thousand kilometres. But these are not normal times. Global warming and increasing desertification has been changing habitats and food availability in Africa, thus making Portugal and all other European spring and summer breeding grounds even more attractive than they used to be.
Studies forecast that many of the commonest migrants will continue to spend as much as two months longer in Europe before returning south in the autumn or winter - and that an increasing number may cease to be long-distance travellers ever again.
A lot of storks and swallows, which are particularly familiar species in Portugal, have given up tackling the hazardous crossing southwards across the Mediterranean Sea and the Sahara desert. They find the year-round environment here is more than adequate.
House martins and cuckoos are among the first and most obvious arrivals here in February and March, but instinctively they are finding it is not worth the effort when Winter environments and food supplies are more plentiful in Europe nowadays compared to a couple of decades ago.
Migrants prepare for departure by consuming as rich and abundant a diet as possible. Even so, there is still a strong possibility of exhaustion on the way. Not only that, they have to depend on their instinctive but still not fully understood ability to navigate over vast distances.
While greater numbers of normally migratory individuals are residing here, Bird International and the RSPCA reckon the overall population of birds in Europe has decreased by around 600 million since 1980. Most of them are common species such as sparrows, starlings and skylarks. Many have been wiped out by agricultural developments, land clearance, air pollution and insecticides. The research shows that some other species have increased by roughly 300 million, hence the net figure of 600 million. The equivalent population decrease over the same period in the United States and Canada is estimated to be more than two billion.
Complicated as all this may seem, nature is simply being forced to adapt as best as possible in line with Charles Darwin’s theory on the survival of the fittest. In this regard, recently published research using data collected over decades shows that some bird species are adapting to global warming by losing weight, slimming down and slightly extending their wing lengths in order to be more efficient in cooler climes.
Bids that prefer relatively high-altitude living are moving higher in hilly or mountainous areas if warming temperatures demand this. Waders in Portugal and elsewhere will have to find alternative wetlands because of droughts created by climate change. The Portuguese Institute of Meteorology says the current drought here, which started last November, has worsened and now 54% of the country is experiencing moderate drought, 34% severe drought and 11% extreme drought.
Mammals and plants are having to adapt too. Some mammals are slimming down and growing longer noses, ears and tails. Fewer seed-eating birds nowadays mean that plants are suffering because of a lessening of seed distribution.
In contrast to native European birds and mammals, so many humans are obese. The world’s human population is increasing. Climate change is not getting the attention it needs. According to the British Museum of Natural History, of the 544 bird species in Europe, 71 are currently threatened with extinction and 34 more are vulnerable. Humans are likely to become extinct too if they don’t mend their aggressive ways, focus more on nature conservation and keep temperatures to 1.5 degrees Celsius above pre-industrial levels.
Written by Len Port
Photo by Birding in Portugal