Greetings, I am Dr. Pat. I have worked with birds for many years. I will do my best to help you.
Birds almost never get constipated. If he is straining to defecate, there are some very serious possibilities. If "he" is a "she", there could be an egg problem. He could have a serious gastroenteritis. He could have kidney problems.
If there is poop collected on his bottom, you need to remove it immediately. You can try warm water and soft cloth, but you may have to pull off the matter.
Gastroenteritis can be caused by many things. the best thing you can do at home is to correct any dietary deficiencies, and add high fiber to his diet (leafy greens are the best; you can offer high-fiber crackers for people (available in the laxative section). This is not for constipation, but it does improve motility a bit.
These signs are not specific to any one disease. And that means it is not fair to you or the bird to guess, there are so many possibilities.You are going to need local help on this, and a scientific and solid diagnosis to find safe and effective treatment.
If you feel comfortable with it, examine the bird thoroughly, using gentle restraint via washcloth or hand towel: do not restrict the chest or hold around the body. Check the mouth and beak if possible, having a good look in there for mucus, redness, masses or anything else unusual. Palpate the tummy for pain, fluid, lumps or anything else. Check all the joints for swelling, pain, and mobility.
Move the bird to an aquarium, box or carrier with soft towels in the bottom, no perch, and food and water in low bowls that can be reached easily. Put the whole thing on a heating pad on low or medium. Keep the unit partially covered, warm and quiet. Go to http://www.awepono.info/awepono/emergencies.html
for some ideas. White paper towels or white cloth towels will show the true color of the droppings.
Do not try to force food or water. You can offer warm cooked rice, pancakes, cornbread, grapes, melon, greens in addition to normal food. Transport as soon as possible.
Pet/feed store medications and home remedies are harmful, ineffective, immuno-suppressive, and make them much worse and may interfere with the veterinarian's diagnosis and treatment. Do not use them.
You are going to need local help on this, and a scientific and solid diagnosis to find safe and effective treatment. It can be made worse by poor nutrition (seeds), seasonal changes, sleep patterns, cage cleanliness, etc. and can therefore be a bit complicated and require more than just a course of antibiotics.http://www.awepono.info/awepono/veterinary.html
I know it is expensive, but you may not have many home options, because the first thing you need a vet for is to find out what is going on. Treatment is only as good as the diagnosis. If you call around, you may find a vet to work within your means. We certainly try to do our best in my clinic.
You need to to take your bird to see an avian-experienced veterinarian
ASAP for complete examination, diagnosis and appropriate treatment. Check http://www.aav.org/association/index.php?content=activeMembersList
for members of AAV in your area (there are listings for Canada) or call your regular vet and see who they recommend; ask if they really have worked with birds a lot. If this were my patient, I would start with complete fecal analysis and direct smear, for multiple parasites; bacterial culture and sensitivity of the feces and choana. Depending on the case I might do a fungal culture. Routine blood work is necessary to rule out other issues. Generally I start them out on antibiotics as indicated by the tests
(I use human antibiotics that are injectable).
Your bird may need injectable fluids, calcium, antibiotics and many other medications. Act quickly and good luck.
The following guidelines help with basic issues such as nutrition, obesity, good immune status. Surprising how the following can make a bird healthy, and how infrequently birds are ill if they are on the following regimen. No amount of medicine is going to work if the birds' basic needs are not met.
Birds should be on a high-quality, preferably prescription, pelleted diet: I prefer Harrison's http://www.harrisonsbirdfoods.com/products/harrisons.html
or in Europe, try this distributor:http://www.vetafarm.com.au/categories/BIRDS/FOODS/
in Europe, http://www.st-laurent.fr/content/pop/dry_food/birds.html
In addition, they should be offered dark leafy greens, cooked sweet potatoes, yams, squash, pumpkin; entire (tops and bottoms) fresh carrots and so forth. No seeds (and that means a mix, or millet, or sprays, etc. etc.) and only healthy, low-fat high fiber people food. A dietary change should be closely monitored and supervised by your avian vet. http://www.awepono.info/awepono/converting-the-diet.htmlhttp://www.awepono.info/awepono/feeding.html http://www.parrots.org/index.php/referencelibrary/healthandnutrition/
Birds should get 12-14 hours dark, quiet, uninterrupted sleep at night. Any less and they can suffer from sleep deprivation and associated illnesses. They should be covered or their cage placed in a dark room that is not used after they go to bed. They should have access to bathing by daily shower, misting, bath bowl, etc.
The cage material should be cleaned everyday, and twice a day if the bird is really messy. Paper towels, newspaper, bath towels are ok. Never use corn cob, sawdust, wood chips, or walnut shell. Consider getting a large cage that is longer than tall--as birds move in a horizontal rather than vertical orientation; and have several feeding stations. http://www.awepono.info/awepono/maintenance.html http://www.awepono.info/awepono/housing.html http://www.awepono.info/awepono/basic-care.html
Never give grit, gravel sandpaper or cement perches. A bird will eat those to excess when it is not feeling well or if there is a nutritional deficiency. They do not need it at all (an old myth from the poultry days, even poultry do not need it). It can cause an impaction and lead to serious or fatal consequences. http://www.awepono.info/awepono/hazards.html