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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
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.
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.
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.
The author would like to thank the Calgary Zoo for their support and
1. Abramson J, Speer BL, Thomsen JB: The Large Macaws. Fort Bragg, CA,
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:
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,
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,
11. Shumaker R: Treat tubes for orangutans. The Shape of Enrichment 1:
12. Atkinson K: Fruit stringer for bats. The Shape of Enrichment 3: 10-13,
13. Hagen M: Nutritional observations, hand-feeding formulas, and digestion
in exotic birds. Semin Avian Ex Pet Med 1: 3-10, 1992