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Formulated Diets, Seed Diets, and Behavioral Enrichment
by Louise Bauck
BSc, DVM, MVSc.
Director of Veterinary Services, Hagen Avicultural Research Institute
The feeding behavior of a pet bird such as the African grey parrot is obviously very different from that of its wild counterpart. The foods themselves are different, as are the methods of procurement. Artifacts of captivity such as clipped wings, cage living and food/water provided in a convenient dish at the end of the perch may produce some behavioral effects that extend beyond feeding time. The purpose of this discussion is to look at some different feeding methods and speculate about the role of enrichment in feeding.
Feeding Practices in Wild Psittacines
Some pet owners have drawn conclusions about the suitability of a captive diet based on its appearance. Many pet owners are reluctant to depend on a formulated diet because of its uniformity. A seed mix is perceived to have more variety and behavioral enrichment qualities. Anthropomorphization should be avoided. Many wild species of parrot have a very uniform diet. The hyacinth macaw has a diet consisting almost exclusively of the fruit of the acuri palm(1). Other species may be more opportunistic. The Puerto Rican parrot is known to have ingested the fruit, leaves, bark, vines and/or other portions of at least 58 species of plant material indigenous to the habitat studied(2). From a behavioral enrichment point of view, the method(s) of obtaining or processing food may be more important than its appearance.
Foraging behavior, food handling and food processing are all complex learned and innate behaviors necessarily influenced by other flock members, parent birds, and foods available. A study performed in 1985 by Magrath and Lill(3) characterized the "time activity budget" of a wild psittacine, the crimson rosella, in its native Australian habitat. They divided the birds' time into 10 behavioral categories: 1) foraging (reaching for, manipulating and ingesting food items; 2) resting (perching immobile or with movement of head only); 3) resting alert (perching with some body movement); 4) maintenance behavior (autopreening, bill wiping, scratching, shaking, stretching and bathing); 5) climbing or walking (locomotion for more than one body length without feeding); 6) flying; 7) billing (use of beak without associated feeding); 8) agonistic behavior (chasing and fighting); 9) reproductive behavior (including nest selection and maintenance); 10) vocalizing. Although the time activity budget differed seasonally, young rosellas in this study spent a mean time of 67% in feeding/foraging and only 7% of their time in resting. Other species may have similar time investments for feeding behavior. In some cases the investment is made in searching for food and in some cases in processing it. For example, the gang gang cockatoo habitually feeds on the very well protected nuts of the eucalyptus tree, expending a considerable portion of its time on simply exposing the edible portion of the item.
Seed Combinations with Formulated Diets
In an effort to provide both behavioral enrichment and nutritional variety, some managers will serve a wide variety of items on a daily basis. The majority of pet owners will also leave a seed mix or seed and formulated diet combinations in the cage 24 hours a day. Fresh foods are generally offered erratically. The net effect of these practices is to complicate nutrition, particularly where a pair of birds is concerned. Balancing fat, vitamins and minerals is difficult enough with our limited knowledge of avian nutrition. Adding factors such as who ate what and how much increases guess work. Worse, over and under supplementation of vitamins becomes more of a problem. Manufacturers may be concerned about excesses of nutrients like vitamin D3 or calcium and are careful to put in levels just sufficient to avoid deficiency disease(4). If significant amounts of seed, beans, rice or pasta are consumed along with a formulated diet, the total amount of formulated diet consumed drops. Most psittacine species have a food intake largely determined by caloric need(13). Ullrey et al determined in 1991 that pet birds are not necessarily capable of making discriminating choices for their own best nutrition(5). Therefore, caution is warranted when using seed or other foods for behavioral enrichment, as total nutrition may be altered.
Many zoos invest considerable time and energy into preparing elaborate and succulent looking meals for psittacine species. The Metro Toronto Zoo conducted a study in 1995 that involved a pair of Major Mitchell's cockatoos(6). These birds had always had access to seed in varying amounts. In the study, a combination of commercial psittacine pellets (80 grams), mixed zoo feeds such as dog chow, monkey chow, etc. (80 grams), finely chopped fresh and dried fruits and vegetables (70 grams), commercial parrot seed mix (50 grams) and a small amount of vitamin mineral powder were mixed together daily and offered to the birds. Refused food was carefully collected from the bowl and floor each day. A "control" bowl was used to compensate for moisture loss and items were weighed each day. This study showed that although fruits and vegetables were sampled, thrown, or moved, very little was actually ingested. The study also removed seed for part of the trial. When seed was present, less of the other items were consumed. When seed was not present, the birds accepted more variety. This may be due to the high fat content of most seeds, which tends to enhance palatability. The seeds are selected first and make up most of the caloric need.
What about habitual eaters of formulated diets? Do they also become reluctant to change their dietary habits? At the Hagen Avicultural Research Institute in 1994, a study was conducted to see how the sudden availability of seed might alter the nutrition of breeding pairs habituated onto formulated diets(7). Birds were available that had been on formulated diets for 5 or more years. No other fruits, vegetables, seeds, or treats have been given in that time. However all of the birds (when donated or acquired) had originally been on seed diets. The formulated diet used in this case(a) had a high fat level in relation to conventional avian pellets, but was still significantly lower in fat content than sunflower, peanut or safflower seeds.
In the study seed as well as nuts and dehydrated fruits were made available to 37 pairs of parrots during their breeding season (May to September). A similar number were maintained on the formulated diet alone. A species or a group difference seemed apparent. Many of the Amazona group readily ate the seed and nuts shortly after their introduction (26 out of 28 pairs). Most continued to eat the formulated diet as well (to an unknown extent on an individual bird basis). However, only 2 pairs out of 11 non-Amazona pairs would consume the seed offered. Is this because Amazona species are more opportunistic in nature? Are some other species more reluctant to utilize "novel" food items? Do the Amazona species seek out high fat food items like seed to a greater extent? Does the colour or appearance of the food influence its selection and provide enrichment? If breeding performance is any indication, in this case no significant enhancement was noted. Control pairs of matched species bred with approximately the same success as those offered the novel food items.
At the Metro Toronto Zoo, seed may be scattered on the cleaned floor of parrot exhibits for "behavioral enrichment"(6). The differing form, texture and appearance of seed is not used for variety in the diet (which is already "varied"), but more as a treat which causes the birds to mimic "foraging" behavior (searching). Adding branches, leaves, or even shavings to clean areas of the floor allows seed to be hidden. Once found, removing the shell from sunflower seeds takes less than a second for most birds, but other seeds or nuts can be more time consuming. Large parrots may enjoy whole macadamia nuts, brazil nuts or walnuts, all of which may cause significant expenditures in the time budget. The high fat content of most seeds and nuts promotes their palatability and motivates the bird to spend the time necessary to ingest the treat.
Behavioral Enrichment for Pet Birds
In addition to food oriented strategies, many behavioral enrichment methods are possible for captive birds. Chewable and manipulative toys, mirrors, models, baths, special perches, flights, musical devices, bells, and nests are all possible and used with many pets. These methods compete for fractions of the time budget, using up time that is otherwise left over from the loss of foraging behavior. Some authors have speculated that feather picking, plucking, and other forms of self mutilation are related to "boredom" or more correctly, loss of activity. Time used for another normal behavior such as self maintenance may be increased to an inappropriate level. Feather mutilation behaviors may start as simple overgrooming.
Loss of activity can also result in other problems such as obesity and hepatic lipidosis. Behavioral enrichment may often be provided for pet parrots by simply allowing and encouraging flight. If a large and safe room can be devoted to exercise, or if a flight cage (indoor or outdoor) can be constructed, many benefits will follow. Some owners allow flight seasonally, maintaining clipped wings during other portions of the year. Exercise can also be obtained without flight, but is usually more problematic. A newly employed exercise device for parakeets is the common plastic hamster wheel(b). Parakeets enjoy and use these devices in exactly the same manner as a hamster, running on the inside for extended periods of time, for no apparent purpose other than exercise. Entrance into a breeding program also provides many enrichment opportunities. In some species of parrot, successful nesting may be preceded by many days or weeks of excavation activity. The provision of a rotting log with a nest cavity started can promote this time expenditure. Commercial equivalents are now available for small species like the parakeet(c). Pet owners can also follow the lead of many zoological institutions and consider the entry of the bird into a regular training program. "Tricks", commands, and supervised flights are frequently used to educate or entertain the public, while making up an important part of occupational therapy for birds with compulsive behavior(s)(8,9). The training program presumably replaces some of the energy expended in social interactions or foraging. Enrichment devices are also available that utilize non-food rewards. Examples include commercial toys available for parrots(d) and small birds(e) that produce a short tune when the bird presses a button or moves the toy.
Feeder Puzzles
Zoological institutions are increasingly interested in "work to feed" methods or devices like feeder puzzles. These strategies increase the amount of time and/or activity required to obtain food. Natural foraging behavior may simply be imitated (scattering or hiding food in the enclosure) or a labour intensive puzzle may be used (complex packages or simple machines). The type of food selected may be either treats or regular food. In the latter case, part of the normal daily ration is normally removed from the feed bowl.
Long before enrichment was popular for pet owners and zoological institutions, psychology laboratories pioneered the use of simple machines to dispense food to experimental subjects as a reward. These devices usually required an action, followed by a cue, then the dispensing of a single food item. The action might be anything from pressing a lever to pecking at a light or shape. A simpler device is commercially available for hamsters(f), where the hamster must press on a lever-like pedal to initiate the gravity dispensing of a treat. This device might easily be used with small psittacines.
Several basic designs are popular for use as feeder puzzles or enrichment devices in zoos. The "feeder ball" consists of a multi-chambered, complex shaped ball, cube, or icosahedron. Feed nuggets are added to an opening and the ball is turned or manipulated until the individual treats are scattered throughout a complex interior(10). The ball must be turned many times inside an enclosure to release all the food or treats, usually one by one. Commercial equivalents are now available for the dog and the horse. A modified homemade approach was used by us to make a "reel" type dispenser. An empty large plastic electrical wire reel with hollow tubular center was transformed into a rolling dispenser. Holes were drilled into the central tube (1/4" bit on a power drill). PVC plumbing fittings were used to block the ends (sleeves secured with glue gun) and make it refillable. The parrot must roll the reel about the floor of the cage or flight to slowly dispense treats, usually one morsel at a time as they fall through the 1/4" openings.
The second major design is similar to our reel feeder. PVC tubes with plumbing fittings are used as a hanging puzzle. Holes are usually drilled through the pipe wall at the top end and the tube is hung vertically. At first it is easy to remove the food or treats as they are in close contact with the holes. Later it is necessary to tip and roll the pipe on the end of its chain to get all the food out. Some parrots are better at this than others. Similar tubes are used for primates(11). Tubes may also be hung horizontally and fitted with clear acrylic sleeves that block some of the slots until moved aside. Another basic design is that of the fruit string (12). A favourite treat such as chunk of raw corn cob is secured onto the end of a string. The string is tied to a perch and the bird must learn to pull up and secure the string to reach the treat. Each time it is dropped, they must repeat.
For those who would prefer to purchase, several options are available. In Canada, one design can be made from a simple toy holder(g) that secures a rawhide shoe(g), toe down. The shoe is filled with anything from brazil nuts to formulated diet. Even after the food is gone, the shoe provides many hours of activity. Corn cob wheels may also be held by the same device. A popular puzzle from the U.S. is the clear slotbox(h). This hanging clear acrylic box is simply loaded from the top, but gravity ensures that the parrot will have a difficult time removing treats from the narrower width of the slot at bottom. Other clear acrylic boxes have rotating sections or openings(h). Metal chambers are also available that require wing nuts, washers, and bolts to be removed before access to the interior can be gained(i). A leather treat sack(j) with multiple holes of varying sizes is available in the U.S., as is a commercially made hanging PVC pipe food dispenser as described above(k). Another chambered treat box design utilizes a top that must be slid up on the suspending chain while a treat is removed(l).
Safety and Occupational Therapy
The use of one or more of these enrichment strategies to help in the therapy of a parrot with feather or self mutilation problems may be useful. Psittacine birds have a large and powerful beak, designed for frequent use in the procurement of food, water, and nesting sites. Replacement of these functions with something other than self grooming or inactivity is the goal. Work to feed strategies may require that part or all of the daily ration is removed from the standard feed bowl. In some cases daily weights are recommended, along with careful monitoring of the droppings. Commercial or home-made devices can be part of an occupational therapy program. However, in all cases, consider both the safety and hygiene aspects of each method. Enclosure floors must be kept clean if food is to be hidden or scattered. Escape and other hazards must be addressed if wings are left unclipped for extended periods of time. Head, foot, and toe entrapments must be considered with reference to the fastener, chain, and holes or openings in any toy. Fasteners must be safe for the species intended. Nails should be clipped on parrots using toys with ropes and string. Refillable puzzles should be machine washable or disinfected in some other manner. Hardware should not become a source of zinc poisoning. Owners are cautioned that all toy use should be supervised until and unless the owner is convinced that a particular toy is safe with their individual bird.
Products Mentioned
a) Tropican(r), Rolf C Hagen Inc, Montreal.
b) Plastic Hamster Wheel, Rolf C Hagen Inc, Montreal.
c) Kozy Keet Playnest, Wesco Pet Inc, Carlsbad, CA.
d) The Jukebox, Pet Warehouse, Xenia, OH.
e) Budgie Buddy, Rolf C Hagen Inc, Montreal.
f) Habitrail SnackBar, Rolf C Hagen Inc, Montreal.
g) Parrot Chew Toy Holder, Rolf C Hagen, Montreal.
Rawhide Shoe for Dogs, Rolf C Hagen, Montreal.
h) Acrylic Toys and Snack Attackers, Pet Warehouse, Xenia, OH.
i) Goodie Gadget, Frasier Products, Denver, CO.
j) Treat Sack, Chewy Bird Toys, Chicago, IL
k) Pic-A-Treat, Fowl Play, Radford, VA.
l) Hide-A-Treat, Pet Warehouse, Xenia, OH.
Acknowledgments:
The author would like to thank the Calgary Zoo for their support and assistance.
References
1. Abramson J, Speer BL, Thomsen JB: The Large Macaws. Fort Bragg, CA, Raintree, 1995
2. Snyder NFR, Wiley JW, Kepler CB: The Parrots of Luquillo: Natural History and Conservation of the Puerto Rican Parrot. Los Angeles, CA, Western Foundation of Vertebrate Zoology, 1987
3. Magrath RD, Lill A: Age related differences in behavior and ecology of crimson rosellas during the non-breeding season. Austr Wildl Res 12: 299-306, 1985
4. Bauck L: Nutritional Problems in Pet Birds. Semin Avian Ex Pet Med 4: 3-8, 1995
5. Ullrey DE, Allen ME Baer DJ: Formulated diets versus seed mixtures for psittacines. J Nutr 121: 193-205, 1991
6. Monitoring food intake in a pair of Major Mitchell's cockatoos, in: 1995 Scientific Proceedings , Nutritional Advisory Group, Toronto, ON, American Zoo and Aquarium Association, 1995, pp 228-243
7. Hagen M: Comparing two feeding methods in an outdoor aviary, in: 1994 Scientific Proceedings, 5th Canadian Parrot Symposium, Toronto, ON, 1994, pp 41-45.
8. Wilson L: Non-medical approach to the behavioral feather plucker, in: 1996 Scientific Proceedings, Association of Avian Veterinarians, Tampa, FL, 1996, pp 3-11.
9. Bauck L: Avian dermatology, in Altman RB, Clubb SL, Dorrestein GM, and Quesenberry K (eds): Avian Medicine and Surgery. Philadelphia, PA, Saunders, 1997, pp 540-562.
10. Gilbert J: Elephant feeder balls. The Shape of Enrichment 3: 3-5, 1994.
11. Shumaker R: Treat tubes for orangutans. The Shape of Enrichment 1: 6-8, 1992.
12. Atkinson K: Fruit stringer for bats. The Shape of Enrichment 3: 10-13, 1994.
13. Hagen M: Nutritional observations, hand-feeding formulas, and digestion in exotic birds. Semin Avian Ex Pet Med 1: 3-10, 1992
