3 January 2023

Small forest birds are increasingly looking for food and often nesting sites in the city. In winter, great tits, green finches, siskins, common redpolls and many other species of small birds live in the cities. Prof. dr hab. Jerzy Bańbura, Head of the Department of Experimental Zoology and Evolutionary Biology, University of Lodz, talks about how to support birds in winter so as not to do more harm than good.

Photo: Prof. dr hab. Jerzy Bańbura

It is good to help birds in winter, you just have to do it sensibly. In recent years, winters in Poland have been rather mild, but even so, there can be a shortage of food in cities. Therefore, well-chosen feeding sites are important for the survival and maintenance of the birds.

– emphasises Prof. Jerzy Bańbura.

When to feed?

In some European countries, such as the UK, year-round feeding of birds is recommended due to the limited access to natural food. – In Poland, there is no such need – explains Professor Bańbura. – It is assumed that the period when birds need our help begins in late autumn and ends in spring. However, regularity is important. – If we already start feeding the birds, we should do it throughout the whole season – emphasises the scientist. – It cannot be the case that birds arrive at a place well-known to them and do not find food there.

On the one hand, winter bird feeding is a factor that lures birds to cities, as a city is not a dream place for them to live. On the other hand, food is also hard to come by in the forests in winter, and there are more predators. That is why great tits and Eurasian blue tits, which are most often seen in cities, emigrate from the forest in search of food.

What to feed?

Bread, cooked porridge, pasta, potatoes or other leftovers from the human table that can harm the birds should definitely be avoided. You can buy ready-made balls in pet shops. – It happens that these balls are well thought over and of value to the birds, but it also happens that they do not arouse the birds’ interest. This may mean that they contain ingredients that are not attractive to the birds, or perhaps even edible – explains Prof. Bańbura. It also turns out that pork backfat is not necessarily a good idea. In the past when good quality, unsalted pork backfat with skin could be bought at the butcher’s shop, it was very attractive to birds, especially on cold days – says Prof. Bańbura.

However, it turns out that the simplest solutions are sometimes the most effective. Sunflower is the best, most valuable and also the most accessible food for birds. You can go for shelled seeds, which are no doubt very attractive to birds. However, it is assumed that those with shells will be much better. Some of their value to the birds will come from splitting the shell itself, both because of the micronutrients it contains and the work the bird has to do in doing so

– says Prof. Jerzy Bańbura.

The only drawback is the large amount of waste around the feeding area, which will have to be cleaned up. We will find shells on windowsills or balconies, or even in window crevices, but this is a price worth paying if you want to feed the birds properly.

Photo: Prof. dr hab. Jerzy Bańbura

Photo: Prof. dr hab. Jerzy Bańbura

Attention, danger!

When one decides to feed birds in winter, it is important to be aware of the fact that the feeding site may become a trap. – It is important to remember that places where food is regularly provided are not only visited by birds, but also predators – points out Prof. Bańbura. – These will include predators directly associated with humans, such as domestic cats, as well as birds of prey, such as sparrowhawks or even kestrels. However, the threat from birds of prey should be treated as something that occurs naturally in nature, while when installing a bird feeder, care should be taken to ensure that it is not accessible to cats.

When choosing a bird feeder, it is also good to pay attention to its accessibility for pigeons, which, especially in cities, are very common and not necessarily desirable. – House-shaped bird feeders that are available in supermarkets will not pass the test in this case; for the same reason, scattering grains onto a tray will not work – explains Prof. Bańbura. – Nets filled with grains or tube-shaped bird feeders, which are only available to small birds will be much better. Nets with a small mesh size are also not bad, so that the sunflower does not spill out and the birds have to put in some effort to get it out.

Forest, urban or migratory birds?

Great tits are partly migratory birds with a nomadic lifestyle in winter. Some of them travel considerable distances of several tens of kilometres or more in search of food. – Our observations of ringed Eurasian blue tits show that some of the birds can travel even much greater distances – emphasises Prof. Bańbura. – We know cases in which a bird has been observed as far as a thousand kilometres from its hatching place. Some populations, especially those from northern Europe or Russia, move over many kilometres, but not all either. In winter we will still encounter great tits in central Sweden, as some of them do not leave their territories.

Research on great tits living in the city was started by scientists from the University of Lodz in the late 1990s by observing birds nesting in nest boxes in the Lodz Botanical Garden and the Lodz zoological garden. – This made it possible to create an experimental system made up of wild birds and at the same time easily accessible to researchers – says Prof. Bańbura. – Thanks to it, we can control the normal course of reproductive processes, but we can also locate more specific research problems on this basis. Twelve doctoral dissertations, two post-doctoral dissertation, dozens of master’s theses and dozens of scientific publications have already been produced based on this research. – Above all, however, we owe our growing knowledge of these birds to this research – adds Prof. Bańbura. We observe the female from the moment she starts to build the nest and through the following stages: egg laying, full laying size, hatching and then the development of the chicks in the nest until they leave it.

During the research, the scientists also compare birds living in the city with those that nest in, for example, the Łagiewnicki Forest. – The research shows that those that have chosen to live in the forest are more successful in breeding, i.e. they bring out more chicks – explains Prof. Bańbura. – However, the winter period is easier for “urban” birds to survive due to, among other things, feeding, which is a very important factor.

It is therefore a good idea to feed the birds.

Source: Faculty of Biology and Environmental Protection, University of Lodz
Photos: Prof. dr hab. Jerzy Bańbura