Foraging as a natural behavior

Foraging is the act of searching for and finding food. Many wild birds spend more than 50% of their day foraging and feeding, particularly in the morning and evening. Because foraging occupies a significant portion of a bird’s daily activity, it likely has social and behavioral importance.

How lack of foraging may affect behavior

Bird behaviors can be divided into four categories: foraging, socialization, grooming or self-preening, and sleeping or resting. In a captive situation, normal behaviors are likely disrupted including foraging. If the ability to forage is removed, that leaves socializing, grooming, and rest. If birds are isolated and have limited contact with humans, this may leave preening and sleep as the only natural behaviors conducted.

Captive orange-winged Amazon parrots (Amazona amazonica) monitored remotely using video camera demonstrated grooming behaviors primarily in the morning and evening. These birds had a complete diet nearby and ingested food 3-4 minutes per hour for a total of 30-72 minutes daily. Birds were inactive for a significant amount of time. This is in contrast to wild parrots such as the Puerto Rican Amazon parrot (Amazona vittata) that forages for 4 to 6 hours daily.

When one behavior is altered or abolished, other behaviors may become emphasized. Such behavior displacement does not mean lack of foraging will lead to overzealous feather grooming, FDB, or inactivity, but it may serve as a risk factor. Although many species differences exist and direct conclusions cannot be made, feather picking may actually be a redirected foraging behavior.

Enriching the environment with appropriate foraging substrates and increasing physical complexity prevented or reduced psychogenic feather picking in young orange-winged Amazon parrots. Physical enrichments included alternate perching sites and moveable, climbing, and swing objects intended to increase the physical complexity of the cage. Foraging enrichments required parrots to chew and sort through, manipulate, and/or open objects to get food and were intended to provide parrots with an opportunity to perform some amount of work to retrieve food. Foraging was associated with significantly improved feather scores, and investigators strongly recommended a varied enrichment protocol for all captive parrots.

Psittacine species are not the only birds reported with FDB. In chickens (Gallus domesticus), inability to access substrates appropriate for dust bathing or foraging is highly correlated with feather picking.

Additional support for foraging may come from studies in other avian species. While it may be assumed that a foraging bird would attempt to obtain food as efficiently as possible to reduce the risk of predation and maximize energy stores, both pigeons (Columba livia) and domestic fowl preferred to peck at a key to find grain rather than eat the same freely available food. Starlings (Sturnus vulgaris) chose to obtain a high percentage of mealworms by searching through covered holes rather than freely from a dish.

Stereotypic behavior

Stereotypies are abnormal, repetitive, functionless behaviors that most commonly develop in animals kept in barren environments. While the cause is not completely understood, stereotypies may develop in captive environments where highly motivated behaviors are thwarted, functional goals are unattainable, or behavioral competition is low.
Four distinct phases of behavioral change characterize the development of stereotypic behaviors.

1. Ritualization: Behaviors become less variable over time.
2. Emancipation: Behaviors are elicited by a greater variety of environmental stimuli.
3. Establishment: The behavior becomes fixed in routine actions even when the environment is modified.
4. Escalation: Stereotypies become more frequent and occupy a greater proportion of time.

Oral and locomotor stereotypic behaviors have been described in pet birds. Locomotor stereotypies involve repetition of an identical pattern of movement such as pacing (walking back and forth across the perch), perch circles (in which the parrot walks the length of the perch, climbs the side wall of the cage, climbs across the top of the cage, and down the opposite wall), corner flips (small circles in a top cage corner), or repeating an identical route around the cage over and over again. Oral stereotypies involve repetition of identical oral movements, possibly within an identical location in the cage. Oral stereotypies include wire chewing, chewing movements but with nothing in the mouth, manipulating food items in the mouth over and over again, and dribbling (dropping and picking up an object repeatedly).

In a group of orange-winged Amazon parrots, 96% of birds performed locomotor and/or oral stereotypies. Certain individuals spent up to 85% of their active time performing these abnormal behaviors. Birds introduced to enrichment performed significantly less stereotypy. Also, behaviors were primarily limited to locomotor stereotypies in enriched birds, suggesting that foraging may have significantly reduced the incidence of oral stereotypies. Foraging enrichments were also used more frequently than physical enrichments, and physical enrichments were often used to gain access to foraging enrichments.

Declines in stereotypies are gradual with the introduction of enrichment, and resolution follows distinct phases. First there is a silent reversal phase that precedes significant behavioral changes or attenuation.

Practical applications of foraging

While feather destructive behaviors (FDB) are common, their causes are often complex. Many approaches to management of FDB have been proposed, and management concerns that should be addressed include:

• Socialization with “bird confident” people
• Dietary modification as needed
• Underlying disease
• Environmental stressors
• Increasing availability of toys and encouraging play activity
• Keeping the bird below shoulder level, and
• Making a conscious effort not to encourage feather picking.

Foraging is another tool to manage abnormal behaviors in birds. In addition to the basic management changes listed above, ask owners to incorporate foraging strategies into bird daily activities (Video clip 1). Gradually introduce foraging until it is used as the main food source by the bird.

Video clip 1. A “treasure chest” toy is used to hide dry food items from a Quaker parrot (Myiopsitta monachus). Video clip provided by Dr. M. Scott Echols.

• When away from home, instruct owners to provide a small amount, if any, food in the cage.
• When home, instruct owners to place the bird on a “foraging tree” away from the cage. The foraging tree is offered as a separate structure that provides multiple areas to climb and suspend toys and foraging devices. The tallest section or branch should be shorter in height than the level of the owner’s shoulder. Construct foraging trees from scratch or modify bird tree stands, perches, or cage materials.
• Use foraging toys that require the bird do some action to retrieve food. There are multiple levels of difficulty. Begin with simple toys and gradually increase complexity.
  • Simple toys include crumpled paper with food inside, paper covering a food bowl, and holes drilled through wood with food inserted.
  • A piece of food tied to a rope and hung from a branch, food hidden in opaque containers with a simple cover, and food hidden in see-through containers with a simple opening mechanism are all examples of intermediate level toys.
  • Advanced foraging toys include puzzle toys filled with food, toys that require the bird to untie knots or open latches to get food, and toys consisting of relatively durable materials such as untreated wood that require chewing apart to get to food.

If the owner’s work schedule requires the bird be kept in its cage throughout the day, hide food in foraging toys within the cage (Video clip 2).

Video clip 2. Foraging can be an active part of a pet bird’s day as shown here in an African Grey parrot (Psittacus erithacus). Video clip provided by M. Scott Echols.

To more completely understand how to build a foraging tree for captive birds and create other foraging toys, check out the Captive Foraging DVD (Fig. 1).

Captive Foraging DVD by M. Scott Echols.

References