NATURE: Imagine surviving a drought, only to be served poison

So many have commented on the shortage of swallows, sand martins and house martins this year that we just have to ask, why is it they are in such short supply? What chance do they have of making a full recovery?
The bad news (it’s always better to get this out of the way first) is that parts of Africa are more severely affected by a warming world than we can possibly imagine. The droughts, heatwaves and other extreme events suffered in that part of the world are beyond our comprehension.
For instance, when we learned of last winter’s drought in the Sahel – the transitional zone between the arid Sahara to the north and the belt of humid savannas to the south – we thought little enough of the sand martins that spend their winter in that normally watery oasis before coming to Ireland to breed. So when they turned up in such small numbers back in April, we didn’t immediately make the connection.
But they didn’t do well in their newly dried winter quarters. In fact, so few were the survivors that some prosperous colonies in this country have remained uninhabited this summer.
However, the birds that did make it here have fared reasonably well. Some are currently raising their second brood of chicks, and if we get those fine few weeks we are looking for, a third clutch of eggs cannot be ruled out.
A good and healthy outward migration might be followed by a kind Sahel winter, and then we shall have good numbers returning next spring. But what can we do to help in the meantime?
Some things need not be spoken. We are all aware of the damage done by weedkiller, for instance. Or are we?
It seems the country has gone mad with all the spraying and killing taking place, even as the world heads into an unprecedented, human-inspired biodiversity crisis.
Do we not know that honeybees forage over a five-kilometre radius from their home hive? Are we not aware that even the tiniest amount of herbicide inadvertently delivered to the hive by any number of bees will accumulate, until such levels of toxicity are attained that poor bee health and even untimely death are bound to occur?
Bumblebees fly less far to forage, but will travel up to a kilometre from the nest to find the best food. Again, they are highly susceptible to the effects of chemical sprays.
We know, of course we do.
But isn’t it better to have our greenery turned into brownery rather than be pestered by any amount of flying insects, even if they do pollinate the majority of our food crops? It would seem that some think so.
Now think of those birds, spending all day every day gathering their harvest of flying insects, each one of which might be loaded with even the tiniest amount of toxic weedkiller.
Perhaps the chemical load isn’t so great as to kill the insect directly. Yet a daily diet of thousands of contaminated flies will inevitably take its toll, not just on the adult swallows and martins but on their nestlings as well.
It was nearly ten years ago, in 2015, that the World Health Organisation labelled Glyphosate, the active ingredient in Roundup, as a ‘probable human carcinogen’. Still, its use as a pre-harvest desiccant on human food crops continues to expand.
It was long considered that glyphosate degraded quickly on contact with soil. Now we know it can persist in soil and water for up to a year, with a half-life (the amount of time needed to pass before a substance degrades to 50 percent of its original toxicity) of up to 249 days.
We also know something of how glyphosate affects the human body, of the impacts on the developing human embryo and on umbilical cells.
We know that in one study, 87 percent of children were contaminated with glyphosate and 80 percent of urine samples taken from adults revealed detectable levels of the chemical.
While many studies have been conducted on humans, not so much work has been done with birds. That said, The Guardian newspaper reported that British gardens treated with glyphosate supported 25 percent less house sparrows than those that weren’t.
What applies to sparrows likely also does to swallows and martins.
It could be the human family are learning fast enough to avert our biodiversity crisis. In the meantime, how do we tell people or help them to see, or educate them in order to stop destroying the little we have left?
The shortage of birds of various types, of insects, of quality habitat, is a direct consequence of the choices we currently make. The good news is that nature is resilient, if we only make enough room.



•   Michael Kingdon, a naturalist and keen fisherman, lives on the shores of Mayo’s Lough Carra, the best example of a shallow marl lake in western Europe and therefore an SAC of enormous ecological and conservation importance.