The humble starling has been in trouble for a while. In the 1980’s there were 45 million starlings, now there are only around 3 million, a decline that has resulted in the starling making the IUCN (International Union for Conservation of Nature) red list of threatened species.
Presumably the decline is due to a lack of food and nesting sites with large scale farming being a particular problem. Starlings seek out cranefly larvae that live in undisturbed soil and the last 30 years have seen a change in land use, with very little land remaining undisturbed. This is considered the greatest problem starlings are facing.
We’ve all heard the myth of lemmings jumping of cliffs but here is a less well known, but true, story. It has been revealed in a recent study that in the twenty year period between 1993 and 2013 there have been 10 separate “drowning events” in which between 2 and 80 starlings were found drowned. In 10 of the 12 there were at least 10 birds involved. This however is only what we know about, it is likely there were far more of these events. None of the birds examined showed any signs of disease. The events all happened in the spring and summer and mainly concerned juvenile birds, suggesting a behavioural problem. Birds are known to drown and records are kept of this but the starling is far exceeding expected mortality rates from drowning and so experts and keen to find the reason behind it.
It is possible that juvenile starlings are simply not recognising water hazards and are getting stuck. Starlings are gregarious (travel in groups) and so if they all accidentally land in the water that may explain it. It is also possible that they are getting stuck simply due to not having an understanding of depth and no way out of the water. Many ponds have vertical sides which are very bad for all wildlife as it doesn’t allow any way out. Quite how big a problem this is we don’t know, it currently doesn’t appear to be damaging the population too much and, as the authors of the study state, it is “more of an animal welfare concern than conservation issue”.
However with an already declining population and only a rough idea of the scale of the issue we don’t want to leave the problem unsolved. The researchers are asking in future that anyone finding the birds records factors such as time of day and weather conditions in order to see if there are external factors that are causing the problem. They also recommend installing ramps into places which starlings frequent in order to mitigate against drowning. Until we get more information though, this will remain a mystery.