We British are great bird feeders. We love it. In fact we do it on such a massive scale that scientists have found some birds beaks are changing to become more adapted to retrieving food from feeders. The blackcap in particular seems to be developing a new British sub-species almost entirely driven by our excessive feeding.
Birdfeeders have been shown to increase the chance of survival for chicks and adults at key times of the year, particularly during spring nesting and the harshest months of winter. Not all species of birds are happy to use feeders though, so it does favour more generalist species, who tend to do better anyway. Yet on the flip side many common feeder users have seen dramatic declines in recent, such as house sparrows and starlings, meaning they may need to extra help afterall.
The main benefit of feeders could however be on the human side of the equation. Not only do many of us get a lot of joy from being able to watch birds, studies have shown many benefits to mental health from taking care of something. For the elderly in particular putting out food for the birds is much more manageable than walking a dog or cleaning out a fish tank. On a larger scale it has been shown that humans are more inclined to protect things they care about, and more likely to care about things they can interact with. Many a person has told me how worried they are about this bird or that because they’ve seen less of them at their feeders.
However there are always downsides. Feeders have been shown to increase transmission of disease amongst the avian visitors. Cleaning feeders regularly can help with this, but there’s evidence that the disease which decimated the green finch population was partly spread in this way.
Another negative aspect of feeders is that they attract other, unwanted species. Rats and squirrels are extremely agile and inventive when it comes to accessing bird food. Sometimes the birds make it easy for them by dropping half of what they pull out of the feeders, other times they just get the food themselves. In principle there’s nothing so different about feeding a rat compared to feeding a bird. They are both wild animals, both fascinating and extraordinary. The main difference that swings feeding rats to the negative is the rate at which they breed. With a constant food supply rat numbers can quickly get out of control, and once they have expanded they can have decimating effects on other species. Rats will eat anything, eggs, chicks, other rodents. In many parts of the world the introduction of rats has led to a crash in the numbers of birds species as well as other types of wildlife.
For squirrels the argument is less clear. Grey squirrels do not have rat-like reproduction rates, but they are a non-native species. The increase in grey squirrels has resulted in the loss of red squirrels from many parts of the country. Exactly why is debated, but we know that grey squirrels carry squirrel pox, which reds are more susceptible to. Grey’s are also bigger and more generalist meaning they outcomplete and muscle out the reds. However, many people still enjoy squirrels visiting their feeders, and live in areas of the country unlikely to see the return of the reds any time soon, so I would put it down to personal preference as to whether you provide your squirrels with a nut and seed buffet or not.
Our problem with our feeder was rats. We’ve also had a grey squirrel and a mouse visiting the feeders, but I was less concerned about these. Reading up online many suggestions were put forward, but most of them seemed impractical or cruel to me, from poison to sweeping up all the dropped food. The one that looked most promising was the idea of mixing chilli powder with the birdseed. The spicy taste we associate with chillies is a chemical called capsaicin. Evolutionary theory states that it may at first have developed to discourage insects from damaging the plants, but in time prospered because it prevented mammals from eating the fruits whilst allowing birds to have their pick. This is thought to benefitted the plant because birds are more likely to carry the seeds far away, rather than drop them close to the original plant. Chilli seeds are also fragile enough that a mammal gut can digest them, but they can pass through a bird unharmed. It’s therefore been found that birds are unaffected by the capsaicin chemical, whereas mammals get the full force of its unpleasant heat. Humans of course have bucked the trend and many of us now relish a spicy curry or chicken chilli glaze.
Therefore, mixing chilli powder with your birdseed should have no effect on your feathered friends but put off anything with fur. For us this meant losing our mouse and squirrel too but I was pretty sure they could get their snacks elsewhere. The best thing is that the chilli won’t harm any of the rodents that do take a nibble, just put them off the next bite. The RSPB guidance says to mix in enough chilli that the seeds are well coated, but not hidden. They suggested shaking it all together in a plastic bag, but I found stirring it together with spoon worked just as well.
It’s hard to be certain if it’s worked but, having spotted a few rats before the change we’ve not seen a single whiskered hairy face at our feeders since and the birds are happily chomping down the food. Some caution should be taken if you have a dog and no catching plate under your feeders to prevent food landing on the floor, as chilli will upset your dog’s stomach if he or she eats it. However, my dog is a regular hoover, even eating non-edible things like paper quite merrily, and he walked straight passed the chilli covered seed and nuts, clearly as put off by the chilli as the rats. The one downside is that the chilli turns the inside of the feeder red, but that should encourage me clean it more often. Family members similarly brought a spray to discourage squirrels from their feeders, and found it dropped their daily squirrel count from three to zero overnight. Looking on the label this too was simply chilli. You may feel more comfortable with a spray, however environmentally and economically a massive pack of chilli powder has less packaging and costs less over time.
So overall I’m very happy with the chilli method, and I promise to update if the rats make a return or my dog developes a taste for spicy nuts.
A year of firsts 