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Wild Baby Bird Diet Blog

Ron Hines DVM PhD


On Wed, Jul 13, 2022 at 4:35 PM, T.A. wrote: 
Dr Hines, thank you for the blog posts you’ve been sharing. Would you consider sharing your experience with the differences between feeding nestling birds with and without crops, specifically passerine/perching birds – maybe in a blog post? I had found some sources that suggest that growing birds should always have full crops, but also that impacted crop/crop stasis/sour crop is a risk, potentially heightened when using kitten chow as a feeder (as in rehabilitation settings). In my inexperience I have sometimes found that I can see food in the open mouth when feeding after a few bites, even though the nestling is still gaping and hungry. But I’m not sure if this is normal in passerines or an indicator of some crop condition. The food eventually descends and the nestlings seem comfortable. But another fear is underfeeding out of unnecessary caution or even causing the above complications or other ones because of underfeeding. 
Sincerely, T. A., South Dakota

I don’t suppose that there are two wild bird rehabilitators in America feeding identical diets or using the same feeding techniques. So it’s always good to know what works for others. My techniques you can read below. Send me your diets and techniques and I will post them at the bottom of this page. RSH 

Hi Ms. A,
Sorry I haven’t kept my promise to write an article especially for you. Its just been one thing after another keeping me away from my website. You asked me if a baby bird’s crop should always be full. I believe that the answer to your question is no. Although foundlings beg for food, over feeding is not healthy. Feed less than they would accept but feed more often. A bird’s crop is composed of smooth muscle – just like your bladder. And just like the bladder, it is unhealthy for it to always be full and stretched. Over time, the crop muscles will become flabby and lose their ability to fully contract. That is an invitation to candidia yeast overgrowth and trichomonas. (read here & here

Doves And Pigeons

You can read an earlier article specifically on dove and pigeon diets here. My baby whitewing doves this summer are getting a mixture of about 80% Gerber’s instant baby oatmeal, 20% Kaytee Exact small parrot and cockatiel powdered diet, two raw beaten large eggs and about a quarter teaspoon full of powdered egg shells. No mourning or inca doves have come in – probably because we are in a severe drought. I have a Krups electric coffee grinder. It powers the eggshells so fine that it behaves more like smoke than coarse powder.  So do it on your porch or patio. You can pick one up at Walmart for $18.88.    This is the first year I have added the Kaytee Exact and powdered egg shells and eliminated the unflavored soy milk which was calcium fortified. The coffee cup is a link to my article on dove and pigeon diets of the last few year. Unflavored soy milk had a very short refrigerator life before it soured. Two thirds of it I had to throw away. The Kaytee Exact™ I added because I have so much of it and had used it for years to raise parrots.  I keep the Kaytee containers in one of our freezers. The Kaytee also makes the final product smoother “more syringable“. Probably because of the enzymes it is said to contain. I have so much of it be because so many baby doves come in along with a container of Kaytee Exact. People run to Petco, and buy some, planing to raise the orphans themselves and then, when they realize how much work that is, they drop them off with me.

All the ingredients, before and now fit, into a 4 inch-tall coffee cup: First I add the powdered ingredients until it fills a bit over half the cup. Then I add enough water to cover the dry ingredients making the cup about 3/4 full. Then I mix it with a spoon. Then I put it in our microwave for 1 minute. Then, when it has cooled, I add the raw eggs – but not the shells. Then I beat it all with a spoon until the egg whites and yolk are unrecognizable. That is best done in a bowel. After that, I tablespoon it into little disposable condiment cups with snap on lids. I freeze those until I need them. I once bought a thousand clear plastic disposable 3 ml laboratory pipettes. for another project. The tube portion tapers and I cut the end to the appropriate correct diameter for the bird (approximately a quarter of the diameter of their neck). A quick pass of the cut end through a butane cigarette lighter flame polishes it. If your food mix is the right consistency, you will feel and hear a slight pop when the pipette in or near the crop is empty. That is the residual air in the pipette. Don’t continue to squeeze after that because you are just filling the crop with air. The white winged doves in this photo were about a day and a half old when they came in. One weighed 25.0 grams and the other 27.6 gm. They were about two days old. That photo was taken 7 days ago. Today they weigh 63.6 g & 72.2 gm. But I get them in even younger:   I am feeding the two above about 5 times a day now. Less amounts but more frequently for the first few days. Two more, about 4 days old, came in today while I was writing this. I always wash my hands vigorously, then I put my finger into the cup to check for hot spots before I use any recently microwaved batch of food. If that’s not for you, just drop a bit onto your forearm like you would for a human infant. Before feeding I check to be sure their crop is empty. I gently massage the crop it a bit. I feed the mix quite soupy – about the same consistency as salad dressing comes out of a bottle. The biggest threat is crop stasis due to over-distending the crop that leads to trichomoniasis.  Another is slow crop emptying due to too low a  body temperature. If I see small bubbles on the mix, as occurs late in the day when a batch has been at room temperature. I taste it. If it is not a completely neutral bland taste, I discard the batch. I am not sure that there is a need for that. It’s just what Virginia Moe taught me to do so long ago at her rehab center in Chicago. Actually the bubbles are the Beginning of fermentation. Fermentation causes a slightly sour taste. However, that fermentation neutralizes phytic acidand could even render the oats more nutritious and creamier.  (read here

Songbirds

            

Songbird doesn’t mean that all of these birds sing a peasant tune. The proper term for these birds is passerine or perching birds. Raptors and owls (stringids) perch too. But they have their own separate designations.

Today I am feeding three baby mockingbirds, a long-tailed grackle and a mystery thrush that I can’t identify. I used my Hamilton Beach blender, set on liquify, to prepare a new batch of diet for them three days ago. It consisted of approximately 40% pre-soaked Purina One+PLUS small breed Lamb & Rice Formula Dog Food, 30% Purina wild game bird starter, 10% Purina Friskies Shreds Chicken in Gravy canned cat food, 10% raw, skinned, deboned chicken quarters with the fat removed and 10% whole raw eggs. The Shreds™ seems to make the mixture smoother, probably because it contains corn starch and soy flour. A diet like this works well for mockingbirds, curved bill thrashers, altamira orioles, kiskadees, green jays, curved bill thrashers, long-tailed grackles, golden fronted woodpeckers and pauraques. It probably would for many other songbird birds as well. It’s just that the ones I mentioned are the ones that are the most frequently brough to me. 

Spatulas

I find these medical spatulas ideal for feeding songbird diet to baby birds. I can visualize the right amount of diet on the tip and I can feed it thicker than I could using an eyedropper or pipette. It is also the safest way I have found to open the mouth of reluctant birds. If you must do that, try not to always feed growing birds from the same side of their beak. Its natural for right-handed people to hold birds in their left hand and pry the beak open with a fingernail of their right hand. Forcibly opening a beak repeatedly that way (always from the same side) can result in scissor beak (aka cross-beak) – as occurred in this hand-raised night jar:      The lady who fed it was unaware of that. 

Temperature

Birds maintained at the wrong temperature do not digest their food well. (read here) I maintain container temperature for baby bird environments at about 32 C/89.6 F. The only time I exceed that is when birds come in chilled (hypothermic) as they do in winter. Thirty two degrees C is considerably lower than the internal (core) temperature of adult songbirds. However the babies are already generating some of their own internal heat through metabolism. If their mother was sitting on them, her skin temperature is considerably lower than her core body temperature and her breast feathers reduce heat transfer to her babies even more. Based on observation rather than experiments, I believe that nestlings digest and thrive best when their surroundings are kept at about 32 C. To do that I plug air conditioner vents, confined the babies to draft-free “nest” containers and use flexible desk lamps with 100 watt Double Life bulbs. I have heat lamps and herp lamps; but I find them cumbersome and dangerous. At 38 C, the doves I raise begin to pant and are in obvious discomfort.

I live in the tropics. Most of the infant songbirds that come in are in heat shock. They are dehydrated. I never feed hypothermic or hypertherimc or dehydrated nestlings. I give them subcutaneous injections of 5% dextrose in 0.45% saline donated by my local hospitals using a U-40 syringe. If that is not an option for you, unflavored pedialyte electrolyte solution, given orally in small drop by drop amounts, is your best option. Never give a second drop until you see that the first one was swallowed.

Insects

Begining when nestlings near maturity, I also offer them diced mealworms, crickets and wood cockroaches in addition to the songbird diet. I attempt to wean woodpeckers over to an all-insect diet using the stumps above. Mealworms fit snuggly into the pre-drilled holes. So do sections of nightcrawlers that have been frozen and thawed before feeding. Fresh, wild nightcrawlers carry a number of parasite. (read here) Worm farm crawlers are probably OK – if the worm farm supplying them or you doesn’t utilize chicken manure or hen house litter. For the same reasons, I never feed sowbugs. They transmit quite a few  avian parasites if they fed on bird droppings. You can read about that here.  If you are only raising a few orphaned nestlings, you can collect quite a few wood cockroches and earwigs by laying down 4′ x 8’sections of old carpet, keeping them moist and turning them over now and then for bug harvest.

I have a lot of respect for Mazuri™. Mazuri was once the agricultural division of Ralston Purina Company. But when Nestlé purchased Purina in 2001, their interest was only in Purina’s dog and cat food lines. After all, Nestlé realized that there was no limit to what “pet parents” would pay for their dog or cat’s food. But farmers using Mazuri products knew exactly what their turkeys, chickens, hogs and cattle would sell for at market and weren’t about to pay more for their feed than they would eventually earn from the livestock’s sale. So When Nestlé acquired Purina, the Purina Mazuri Division was sold off to Land O’Lakes, the a butter and dairy cooperative. Land O’Lakes renamed what they bought Purina Mills™. Mazuri’s nestling Handfeeding formula is primarily composed of powdered whole dried egg and chicken meal. Powder whole egg is is about 48% protein and 44% fat. Chicken meal is about  65% protein and 12% fat. However besides vitamins, Mazuri adds rosemary extract, a product that contains many polyphenols which naturopaths believe aids in relieving colic and excessive digestive tract gas. They also add probiotic lactobacillus bacteria. All three of those bacteria are biproducts of the cheese-making industry – something Land O’Lakes has a lot of. None of these bacteria have ever been reported to naturally inhabit the digestive tracts of healthy wild birds or mammals. (read hereAll food companies tend to include ingredients that are in current vogue with the public and readily available.  Whether or not there is any hard science to support that inclusion is really not important to them. That said, Mazuri’s Nestling Handfeeding Formula is probably a great product. I have never had the occasion to use it. If you have, let me know.

Fish Eating Birds

         

I live near the ocean, so I get in a lot of shore and seabirds. I feed them diced or whole fingerling mullet when I can afford to buy them at the bait store. First I freeze them for two weeks because mullet are also a common source of avian parasites such as contracaecum. All the pelicans and cormorants that come in are loaded with those disgusting worms. 200 mcg/kg of ivermectin packed into a fish will destroy those parasites and their pouch lice as well. 

If you are only caring for a bittern or an egret or two, minnow traps like the one in the last photo, placed in a nearby lake, will feed a bird each. I bait it with a “tea bag” of cat food. The seine in the photo will catch even more. However adult brown pelicans eat ~3 pounds of fish a day. I get lots of them in each winter every time a “Norther” blows in. They all have collided with the cement dividing barrier on the road to South Padre Island. See that hereI know a shrimp boat captain who will save his trawler by-catch if I ask him to. Bit I have to drive 23 miles to get them. If  you feed fish, be sure to snip of their dorsal, anal and pectoral fins and feed them head first. It takes several months for their fractured coracoid bones to heal. See the coracoid bone hereIf you feed any of your foundlings fish, be sure to fortify their diet with thiamineMany fish contain thiaminase, an enzyme that destroys thiamine (vitamin B-1). Particularly commonly-sold bait fish like capelin and smelt. At SeaWorld, we packed a mackerel with vitamins before pitching it to each orca. See here

Raptors And Owls

     

I feed these birds thawed frozen rodents as well as trapped sparrows. I know that a lot of wildlife rehabilitation centers feed their raptors, owls and carnivorous mammals the hopeless nestlings and small mammals that arrive with no possibilities for eventual release. The same goes for non-native species. Although rarely mentioned in public, there is nothing unethical about that. Predators have to eat and God sets the rules. And the animals in your care need to learn how to hunt in order to survive. How much of that is hardwired into their genetics and how much requires presentation by their parents or you is unknown. In my youth, I hunted dove, loved to fish and enjoyed hamburgers now and then. But as the years have gone by, I find it harder and harder to kill things. I started working at a veterinary hospital when I was 14. The vets were low bidders on Cameron County’s contract to kill all stray dogs and cats. My job after school was to assist in that. It didn’t bother me much at the time. But it did affect me long term. Since my 20’s I eat no meat, fish or poultry. It is my penance for the things I have done to animal back then and later at the NIH. So my raptors receive considerably more chicken quarters than yours will. I buy the quarters in 10 pound sacs, remove the long bones, the skin and the fat, and then take what remains outside to our sidewalk near a garden hose and pulverize the bones that remain with a hammer. Those chickens are slaughtered at 2-3 months of age. So their bones still pulverize easily. In Florida I used to buy chicken necks in 20 pound frozen blocks. I would pulverize them the same way and feed them to rehab bald eagles. Chicken necks are unavailable to me in quantity now that I am back in Texas.  I get in quite a few barn owl chicks. They should start coming in in the next month or two because here they are autumn nesters. The chicken in the last photo was for one group of barn owls. Once a week they got chicken livers instead. Red meat and poultry is low in vitamins B-12, and vitamin A. Liver is much higher in those vitamins. None of the raptors that come through liked beef liver. I suppose that is due to the bitter taste of bile. They try it, then spit it out. I have someone release hand-raised great horned owls on the huge South Texas ranches – far from human interaction. When barn owls and screech owls are ready to go, I just leave their flight cage feeding door open. They come back at dusk for a free meal for a week or two, and then I never see them again. Never let your rehab owl loose in the daytime. The mockers and grackles heckle them mercilessly.

Killdeer

   

Most often it is an elementary school teacher who brings me killdeers. Since killdeer are ground nesters, children find them in the schoolyard during recess and bring them to their teacher. Occasionally they fall from the flat gravel school building roofs. Like their more plentiful cousins the sandpipers, killdeer are precocial. From the get go killdeer chicks eat small insects that they encounter. I feed them the small insects I find under my outdoor carpet remnants. Many of those insects need to be diced. The same goes for crickets if you buy them. I also feed them grubs I dig out of my compost pile and sun-baked flies. But the majority of their diet is ground up cat chow that has been slightly moistened. What you see coming out of the grinder is mixed ground up bird seed about to be offered to doves not to killdeer. I feed the killdeer with the mill set on a coarser grind. You can also crush the cat food with a mortar and pestle. Once in the yellow jar lid, I drip water on it. You can read more about how I raise killdeer here

Grit

The only birds to which I supply grit are doves that are already eating whole grains. I have a series of colanders and sieves that allow me to select what I think would be the right size. If you rehab galinaceous birds, it would wise to supply them with grit as well. Oyster shell of the proper diameter is another option. 

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Weak Legs In Songbirds

On Aug 9, 2022 F.A. Wrote:

Our tits are hole-nesters that breed in our nest-boxes, but otherwise free-living, so even in our experiments they feed on their own (i.e. we do not provided them with anything in addition to what their parents feed them (mostly caterpillars and some spiders in the case of the tits). Having said that, I have seen these “soft” legs also in tit nestlings. It is quite uncommon though – I have worked with these birds for almost ten years now but the number of nestlings that I have seen with this condition is no more than a handful. However, I know that my colleagues also have experienced this, so even though it happens rarely, it does happen. My own, very anecdotal feeling about this is that it seems to happen at the end of the breeding season – maybe suggesting that it could be due to the fact that some important food source is running out of stock. In general, nestling quality in the tits is almost always lower at the end of the season (most likely because they have missed out on the caterpillar peak). We have discussed this in our research group and talked about a possible lack of calcium that is interfering with osteosynthesis. In both blue tits and great tits it seems that a large amount of spiders in the diet is associated with larger tarsus size (possibly via calcium or some other vitamin/mineral) but I don’t know if a lack of spiders in the diet is what is causing these soft legs. The only thing I can think of is to add calcium to the diet and perhaps also vitamin D3 (to compensate for lack of UV-lighting, which is hard to make up for in indoor settings).

All the best, F.A., Lund University, Sweden

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