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Incorrect feeding

Experience with swift patients in the last few years has led to alarming new discoveries, and in particular, errors in feeding and their fatal consequences are in first place. While insect eating song birds (e.g. swallows, redstarts, redbreasts, warblers, wrens, etc.) recover quickly from incorrect feeding, a wrongly fed swift recovers after a much longer delay and with serious consequences. Wrong feeding seems to lead primarily to liver damage, and secondary plumage damage is often observed. Faulty primary feathers in an aerial (long distance) bird are however a death sentence. Even after a short period on incorrect food, lasting a few days, most young swifts react with loss of feathers or damage to the shaft or feather. Just as serious are frequent problems such as diarrhoea, digestive problems and deformities of the skeleton.


Two juvenile swifts, who have lost nearly all primary feathers after being fed meat. © C. Haupt

Many feedstuffs, which have been proved to be damaging. are disastrous even though they have been used for decades for feeding young foundlings of wild birds, and are still often recommended by specialists. The situation is even worse as many people who find injured birds look for advice from experts who are supposed to be knowledgeable in animal nutrition in general, and ornithology in particular. We can only hope that many of these “traditionally mistaken” persons turn as soon as possible to nutrition of foundlings based on nature. Only in this way can the very different nutritional requirements of foundlings of various species be met, for whom no “universal prescription” exists.

Which foods should be avoided, and what kinds of damage do they cause?

Severe plumage damage after 14 days of feeding on mince meat and “bird food”. © C. Haupt

Raw meat/mince meat

The oldest and most widespread misinformation is that swifts can be fed with mincemeat. If you think about it and observe swifts in nature, you are forced to the conclusion that this is about as true as the proposition that babies are delivered by storks. And if one reads up on the life and nutrition of a swift patient in official books on swift care, it will eventually dawn on the most ingenuous person that no-one has ever seen a swift on the hunt sink its teeth into a harmless cow or pig.  

So get rid of the mincemeat myth, that has cost so many lives! The metabolism of a swift is just not adapted to nutrition via meat, either pure or even spiced. It is incomprehensible how this false logic seems be stubbornly listened to. Perhaps it is because it is just so easy for the carer. Another reason could be that the fatal consequences for the swift appear after a delay. The loss of primary feathers, which happens for nearly all swifts fed on mincemeat only, starts about 8-10 days after the switch from insect food. This is a moment in time when a juvenile swift, if he has reached good enough condition for flight, is already in the air. In many cases he does not even get that far, as other effects of mincemeat feeding are deficiency of calcium in the skeleton and bone deformation, serious digestive problems, diarrhoea, enlargement of the liver and deficiency diseases. Plumage problems range from the loss of single feathers to many kinds of defect in the feather itself, including inadequate growth and total loss of primary feathers. Tail feathers show mostly damage to their structure and incorrect form.

"Mealworms", © I. Polaschek


For a long time, “mealworms" have been recommended for the feeding of insectivorous birds – these are incorrectly named larva of the mealworm beetle (Tenebrio molitor), which can be found in most pet shops. However it is important to warn against long term (longer than 2-3 days) or heavy feeding with these. In their chitin shell, it appears that there are substances which over a prolonged period provoke liver and kidney poisoning.

It seems to exist a coherence between the nutrition of the mealworms themselves and their use as food for birds.
Through our good contacts to foreign partner organizations we learnt that good results can be obtained feeding mealworms to swifts, provided that the mealworms are fed with extremely high-quality and faultless products, such as fresh vegetables and fruit.
Mealworms from pet-shops are mostly badly nourished and have a brownish colour instead of white.

Feeding only with mealworms can also be too limited and lead to symptoms of deficiency and skeletal damage, if they are not fed with proper and healthy things. Particularly common are the symptoms of Vitamin B deficiency. Lack of Vitamin B complexes affects the central nervous system, which begin inconspicuously as refusal to eat and convulsive movements, and within a very short time continues with cramp-like movements (somersaults, head movements, turning in circles), and if not treated leads to irreversible nerve damage and death. In any case, feather damage nearly always appears as well, probably also as a secondary effect due to liver damage. Mostly the feathering remains stuck to the shaft and when it separates, and the feathering is not correctly developed. Loss of feathers is frequent.

For songbirds fed over long periods only on mealworms, there have been observed persistent eye inflammations even leading to blindness, as well as ulcers on the head, inflamed swellings on the feet and joints, and abscesses.


Mealworms – but only the soft white ones which have just shed their skins – can be given as a supplementary food in small quantities (i.e. 4-5 per day) to insectivorous birds, or used as emergency food for 2 or 3 days, if it is not possible to obtain grasshoppers quickly. It must be checked that the mealworms have been fed on fresh, unspoiled food (e.g. oat flakes, apples, dandelions.) If, as one can see in many pet and animal food shops, they wriggle around in their own smelly excrement, they are obviously unacceptable as food.

Broken feathers after being fed on maggots for two weeks. © C. Haupt


Fly maggots, obtainable as “Pinkies” in fishing shops, are completely unsuitable as food for insectivorous birds. Because of their stable, rubbery skin they cannot be digested by the bird’s stomach, so that they are often excreted undigested. Even when they are ruptured (which is not exactly everybody’s preference), they are not acceptable, due to their high fat content, and limited range of nutritient content.br />Swifts which are fed with maggots are usually very emaciated and develop symptoms of deficiency, and severe defects of the major feathers. Frequently these are small, hardly visible cracks in the shafts of the primary feathers, which then break under minimal loading.



Results of “fat-rich” feeding. © C. Haupt

“Insect-", “Fat-" and “Honeyfood"

For a lay person, who finds in a pet or animal food shop a wide range of the most different bird foods, it is impossible to find the correct food for a hungry nestling. Even the proprietor is probably not familiar with the special requirements of wild birds, as these requirements depend on age and species. Often the appropriate food is not in stock. Various kinds of “Insect food" maliciously tempt the bird-lover with photos of swifts and sensitive songbirds. On examining the composition of these mixtures, it is found nearly always that they consist of bakery products, such as waffle crumbs, which are completely inappropriate for the digestive system of an insectivore. After feeding with dry food moistened with water, it has been repeatedly observed that cracks occur in the primary feathers: these swifts are incapable of flight.

If one will or must use crumbly dry food, only pure dried insects may be used (e.g. by “Aleckwa").



Not infrequently, young swifts are fed with earthworms. Earthworms are however not insects, and do not belong to the spectrum of prey hunted by the aerial swift, and they cause severe disturbances to digestion. Even worse, they host certain parasites. From just one earthworm, a swift can be infected by the eggs of worms infecting the trachea, and a few days later become sick. Earthworms should best be left to starlings and thrushes, which are adapted to this kind of food!


Cat or dog food in cans

Swifts who are fed with cat or dog food are usually covered from head to food with sticky, crusty deposits,

stink awfully, are completely underdeveloped, and suffer from severe digestion problems. Their plumage remains limp and dull and does not insulate properly. Without plumage with good thermal insulation, a swift is doomed as it will later fly to 1000 m of altitude, and spend the night there, with temperatures under zero. The various rather ominous constituents of cat and dog food in cans are in no way adapted to the digestive system of an insectivore and can damage it so severely that the bird dies or must be put down. It is imperative to avoid this kind of food, which is so commonly used in lost animal homes!


Juvenile swift, died in agony after five weeks feeding on canary food. ©. Haupt

Other foods

The above considerations are not meant to be complete. Almost everything has been tried, and always with fatal results, as food for hungry young swifts: canary or budgerigar food, biscuits, oat flakes, bread, fruit, hot dogs, spaghetti, porridge, salami, wiener schnitzel – everything, and no bird has ever survived it. The list of unsuitable food can be continued forever, so it is simpler to say: in the beak of a swift belongs only insect food!



Left: incorrectly fed juvenile swift, covered in food and excrement, with severe feather damage. Right: a similar bird after feeding on grasshoppers. Fotos: C. Haupt

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