Session #3007

Abstract

Feather damaging behavior is frequently displayed by parrots kept in captivity and can be a complex and frustrating problem for veterinarians to deal with due to the multitude of medical, neurobiological, and socio-environmental factors that can underlie the condition. While management of the condition is presumably most effective when targeting any and all involved risk factors, the strategic use of enrichment in its many forms can be beneficial in many cases, even those with a medical background. When designing and implementing an enrichment plan, a systematic and goal-oriented approach (which takes the species’ biology and caregiver’s possibilities, as well as the individual’s abilities, preferences, temperament, and [early] life experiences into account) combined with proper documentation and regular follow-up are key to ensuring the end result is tailored to the needs of the individual bird.

Introduction

Feather damaging behavior (FDB), also referred to as feather destructive behavior, feather plucking, feather picking, or pterotillomania, is common in captive psittacine birds, with a prevalence of up to 40% reported in cockatoos (Cacatua spp.) and grey parrots (Psittacus erithacus). Feather damaging behavior includes the chewing, plucking, biting, or pulling of feathers that are accessible to the beak, and usually represents a multifactorial problem, in which a multitude of medical, genetic, neurobiological, and socio-environmental factors can play a role.¹ As such, a thorough medical and behavioral workup, which includes a detailed history, complete physical examination, and (dependent on the findings) additional diagnostic tests, is pertinent to help identify the various factors that could be underlying the behavior.

A targeted approach, which addresses any and all factors that have been identified, is highly recommended when trying to manage a bird with FDB. Should any medical issues be encountered, these should be treated appropriately. In absence of (signs that point towards) an underlying medical cause, a primary behavioral origin for FDB becomes more likely. In such patients, the behavior is considered to originate from either an attempt of the bird to deal with a suboptimal living environment (i.e., maladaptive behavior) or from an altered neurochemistry (i.e., malfunctional behavior). While maladaptive behavior will respond favorably to changes that optimize the living environment to the bird’s needs, this will no longer be the case in birds with malfunctional behavior, as the behavior has become ritualized (similar to stereotypic and other abnormal repetitive behaviors). Therefore, it will be displayed regardless of any inciting stimuli and generally require the use of psychoactive drugs to alter brain neurochemistry and make the bird more receptive to (changes in) its living environment. As maladaptive behavior may develop into malfunctional behavior following prolonged and continued exposure to a suboptimal living environment (hence hindering easy distinction of the two conditions), the use of environmental enrichment is commonly used as the first go-to treatment as this is the least intrusive and most beneficial to the (welfare of the) patient. However, even in patients in which medical conditions have not been ruled out or in those in which the inciting and/or reinforcing stimuli have not been clearly identified, environmental enrichment will promote a more stimulating environment that can help to alleviate FDB by offering the bird a distraction or redirecting the underlying ‘trigger(s)’ or ‘motivation’ for FDB. Thus, regardless of the cause, use of enrichment should be considered an important cornerstone in the management of any patient with FDB.

Environmental Enrichment

According to Newberry (1995),² environmental enrichment comprises “an improvement in the biological functioning of captive animals resulting from modifications to their environment.” Offering enrichment to a parrot will allow it to perform species-typical behaviors, provide mental and physical stimulation, and enable the bird to exert control over its environment, which are all beneficial to its wellbeing. Five categories of enrichment can be distinguished, which include:

1.  Social enrichment: interaction with conspecifics, humans, and other birds or animals through direct or indirect (vocal, visual, physical) contact

2.  Occupational enrichment: enrichment that provides a mental challenge (cognitive enrichment such as puzzles, training, novelty) or promotes physical exercise (e.g., flying, climbing, walking)

3.  Physical enrichment: changes to the bird’s habitat in terms of position, type, and size of the enclosure, as well as the climate (sunlight, temperature, humidity) and furnishings within the enclosure (e.g., perches; substrate; nest boxes; bathing opportunities; gnawing/chewing materials; swings, ropes, and other toys)

4.  Sensory enrichment: enrichment targeting one of the five senses: vision, audition, touch, taste, and olfaction

5.  Nutritional and foraging enrichment: enrichment aimed at stimulating food-related activities

Please note that these categories are partially overlapping one another and that items are grouped according to their most important function.

Enrichment for Behavior Modification

Enrichment is frequently used in the treatment of problem behaviors. In the context of a behavior modification strategy, enrichment can be implemented as part of antecedent arrangement to help reduce the likelihood of the behavior occurring or as a reinforcer (reward) to stimulate alternative, incompatible, or other behavior. In humans, a review of 71 publications showed 265 uses of environmental enrichment, either as a standalone treatment or in combination with behavior manipulations used to either prompt or reinforce alternative behaviors or to block or restrain problem behavior.³ When used alone, environmental enrichment was effective in 41% of the cases, hence indicating its value in the treatment of problem behavior; however, when combined with manipulations of alternate or problem behaviors, the treatment success further increased, suggesting that treatment should preferably include additional behavior modification methods.

Environmental enrichment has also been proven to be effective in the management of parrots with feather damaging behavior. In particular, stimulation of foraging activity is recommended as FDB has been inversely correlated to foraging effort.^4,5 As foraging behavior (i.e., the act of searching for and consuming food) is highly conserved throughout evolution, many species (including parrots) are motivated to work for food even if the same food is freely available (i.e., contrafreeloading). Compared to their wild counterparts, companion parrots are found to spend significantly less time on foraging (i.e., 30–60 minutes per day versus 4–8 hours per day) as food is often readily available in abundance. In absence of appropriate stimuli that promote captive foraging, the motivation to forage may be redirected or displaced to the feathers, leading to FDB.⁶ Provision of foraging enrichment will enable the bird to perform its species-typical foraging activities and fulfill this foraging motivation. In the management of FDB, stimulating foraging activity is considered especially beneficial as it is incompatible with FDB (i.e., both activities require use of the beak and cannot be performed simultaneously). Moreover, the food obtained through foraging may act as a reinforcer that can result in the bird electing to forage over destroying its feathers, if it has equal or greater value than the (extrinsic or intrinsic) reinforcement that is obtained from the feather destruction. Because of food being a primary reinforcer, foraging enrichment also tends to maintain its stimulating value for longer periods of time. It furthermore has the added benefits of increasing activity, providing mental stimulation, and alleviating stress and boredom.

Foraging Enrichment

In essence, four basic strategies can be distinguished to promote foraging in parrots. They include:

1.  Increasing the spatial or temporal variability of feeding (e.g., through provision of smaller, more frequent meals in multiple bowls and/or locations)

2.  Increasing search time for food (e.g., by scattering or hiding food in the enclosure or mixing it with inedible items)

3.  Increasing extraction time (e.g., through use of foraging devices or puzzle feeders)

4.  Increasing the time needed to process and ingest food (e.g., by providing whole food items, larger food particles, or frozen ice blocks with food inside)

For birds that are new to foraging, starting with easy foraging tasks (e.g., multiple bowls, scatter feeding, mixing with inedible items) is recommended, while tasks can gradually be made more complex (e.g., through use of puzzle feeders or a combination of foraging strategies) for more experienced birds. Aside from offering foraging opportunities, the source of nutrition or the food itself can also function as enrichment (e.g., by presenting different types of or novel foods, varying the type of food offered over time or by using seasonal produce, or limiting provision of favorite foods to training or foraging activities).

Other Types of Enrichment

While foraging enrichment is seemingly highly effective in reducing FDB, promoting a more stimulating environment by means of social contact, physical exercise, mental stimulation, chewing toys, sensory input, and other forms of environmental enrichment should also be considered in the therapeutic plan. As previously mentioned, causes for FDB can be multifactorial and complex. In essence, any environmental factor that results in a negative affective state (e.g., stress, fear, anxiety, boredom, frustration) can lead to displaced or redirected FDB that develops in an attempt of the bird to cope with a suboptimal living environment. Both absence of appropriate stimuli, which limits the ability to perform species-typical behaviors (e.g., solitary housing, lack of gnawing opportunities, flight deprivation) and exert control over the environment, as well as presence of potential aversive stimuli (e.g., presence of a predator, exposure to novelty, sudden changes in routine, family structure, etc.) can contribute to FDB and should be addressed appropriately when trying to manage such cases.

Social Enrichment

Parrots in particular are known to be highly social, and lack of social contact can result in problem behaviors (such as excessive screaming to attract attention, anxiety, and FDB). Social enrichment can be achieved through vocal, visual, and/or physical contact with conspecifics; however, for parrots that have been hand-reared without conspecifics and are heavily imprinted on humans, other birds may be a stressor. As such, the parrot’s rearing history needs to be taken into account to help determine whether it will favor a human, conspecific, or other bird or animal as its social companion. In human-bonded birds, the type of interaction with the caregiver is important as well, as too much physical contact may stimulate reproductive-related behaviors (e.g., regurgitation, nesting behavior) that in turn can lead to ‘sexual frustration’ and associated FDB.

Occupational Enrichment

Occupational enrichment will generally also be beneficial to consider in the treatment plan, particularly those activities that promote beak exercise (e.g., exploration of novel objects, chewing opportunities), as these are incompatible with FDB (similar to foraging). Cognitive enrichment in particular is important for highly intelligent animals (such as parrots), allowing them to be mentally stimulated and (re)gain a certain control over their environment. For example, training can be used to teach a parrot specific husbandry behaviors, such as entering a carrier or acceptance of a towel, thereby offering the bird an opportunity to cooperate rather than being forced to undergo these activities. In many cases, such training will require the use of so-called desensitization and counterconditioning techniques, as birds may initially be fearful and therefore hesitant or unwilling to participate in the training.

Physical Enrichment

Physical enrichment encompasses the various physical features of the bird’s living environment, including bathing opportunities (which are important for stimulating preening activity and maintaining optimal plumage condition) and toys or other objects that stimulate independent play. Preference should be given to items that are favored by the bird and elicit its curiosity. Many parrots will favor items that are easily destroyed (e.g., objects made of paper, cardboard, or soft wood). Aside from the type of material, characteristics such as size, color, or texture can also influence the parrot’s interest or aversion to a certain object. For example, many of the larger parrot species will prefer items that can be held in the foot while manipulating it with the beak (so-called podomandibulation). Several studies have shown preferences for certain characteristics within a species that can be helpful as a starting point.^7-10 However, it should be remembered that preferences can vary greatly among individuals, in part dependent on their previous life experiences, thereby emphasizing the need to carefully evaluate the parrot’s responses to the items and objects presented to it and adjusting the type of environment (as well as the frequency with which it is rotated, renewed, or replaced) to their needs. Positive reinforcement, desensitization, counter conditioning, and other behavior modification techniques may again be helpful to reward the bird’s interest and stimulate interaction with the (novel) items provided.

Sensory Enrichment

For parrots, sight, smell, and touch comprise the main senses, thereby emphasizing the need for sensory enrichment by visual, tactile, and auditory stimulation (including offering of different colored items, mirrors, moving or noise-making toys, radio [music] or television sounds; offering of variable substrates, perching surfaces, or toys of different textures; or a change of scenery [novel surroundings]). Similar to physical enrichment, preferences can be highly dependent on the individual.

Designing an Enrichment Program

When creating an enrichment program for a FDB bird, it is highly recommended to use the so-called SPIDER model.¹¹ The model consists of the following.

S: Setting Goals

The goals of the enrichment program should be specified and be as concrete and measurable as possible, clearly identifying which behavior(s) the enrichment tends to encourage or discourage and to what extent. Larger, complex goals should ideally be broken into smaller, achievable goals that contribute to achieving the larger goal (e.g., FDB may be reduced by an increase in foraging time, an increase in bathing time, and initiation of training activities).

Gain in-depth knowledge of the individual (e.g., rearing history, socialization, early life experiences) and natural history (e.g., natural habitat, dietary preferences, social structure, daily activity patterns) of the species involved, which will help determine its biological, social, and cognitive needs.

P: Planning

An enrichment plan needs to be created which specifies the type of behaviors (intended) to be encouraged with the enrichment; the resources needed to create the enrichment initiative; and the location, time frame, and circumstances during which the enrichment will be offered. The available space, resources, and time available by the caregiver should be carefully weighed as this will help to ensure feasibility of the approach. In addition, the species’ biology, individual’s temperament, and early life experiences should be carefully considered, as these will all influence the value that the offered stimuli will have to the bird. Generally speaking, enrichments will have higher value if they are biologically relevant for the species, thereby emphasizing the importance of gaining more in-depth knowledge of the species’ natural habitat, dietary preferences, social structure, and daily activity pattern. In addition, level of novelty offered should be considered, as neophobia and exploration have been tightly linked to species’ ecology, personality traits, and early life experiences.^12-15 Equally important is to ensure that the plan is properly aligned with the capabilities of the individual bird (e.g., offering complex foraging puzzles may not be helpful in a bird that has never foraged in its life), allows the bird to maintain a free choice and exert control over its living environment, and addresses any possible safety concerns that warrant additional monitoring (e.g., a bird may accidentally ingest or get entangled in a toy, offering of enrichment may increase risk for aggression in group-housed birds).

I: Implementation

Implementation should be carried out in a logical and gradual way. Consider timing of and location where the enrichment is offered, as these can be vital to the overall success of the enrichment plan. Also ensure gradual introduction of the enrichment, as too much stimulation and novelty at once can cause undue stress in certain individuals. Challenges should be graduated so that they remain achievable yet allow the bird to continue to learn and evolve, which is important to help prevent frustration of both the bird and its caregiver. For anxious, nervous, or fearful birds, the use of desensitization and counterconditioning techniques may be required.

D: Documentation

Ideally, a detailed record should be kept on when, how, and what enrichment was presented; how the bird responded to it (e.g., type, frequency, and duration of interactions); and on its behavior in general. Video recording may be useful to document enrichment use and should be encouraged where possible. This will help to determine which components of the enrichment program are the most and least useful. Unfortunately, observations can be easily skewed by wishful thinking, available time for observation, and misinterpretation, especially in cases of FDB, as this often occurs at night or when the owner is not present.

E: Evaluation

Periodic evaluation of the enrichment plan will help to determine whether the enrichment has the effects as originally intended on FDB and whether there are any safety or other concerns with its implementation. To accurately assess the value of the enrichment plan, it is essential for the clinician to receive uninterpreted, objective, and accurate observations from the caretaker or to be able to review raw video footage. As an alternative or adjunct method, the use of serial photographs or assessment of the plumage condition, which serves as an indirect measurement of (changes in) FDB, can be considered.

R: Re-adjustment

Modify the enrichment plan by adjusting the enrichment or the way it is offered to optimize its effects on the behavior until the achieved goal is reached.

Following evaluation, modifications may be made to optimize the enrichment plan. Modifications may include removal or modification of poorly used elements (which can be revisited at a later time), addition of more of the well-used elements, or addition of new elements of enrichment. Sometimes changing the way in which an enrichment is offered (e.g., moving it to a new location) can spike the interest of the bird, despite the item being previously ignored. For fearful birds, repeated exposure may lead to habituation, thereby allowing them to become more accepting of objects they initially feared. Complexity, difficulty level, and/or amount of food offered via foraging enrichment can be increased as the bird becomes more experienced. Similarly, physical exercise can and should progress as the bird develops better physical stamina and condition. Training can begin simple and gradually include more (complex) behaviors. Sensory enrichment can be adjusted to the preferences of the bird.

Frequent consultations will generally be required as the process is fluid and requires continuous evaluation and readjustment. Nevertheless, the SPIDER method is helpful and promising to gradually adjust an enrichment plan until it is tailored to meet the needs of the individual bird.

References

1.  Van Zeeland YRA, Friedman SG, Bergmann L. Behavior. In: Speer B, ed. Current Therapy in Avian Medicine and Surgery. St. Louis, MO: Elsevier Health Sciences; 2016:177–251.

2.  Newberry RC. Environmental enrichment: increasing the biological relevance of captive environments. Appl Anim Behav Sci. 1995;44:229–243.

3.  Gover HC, Fahmie TA, McKeown CA. A review of environmental enrichment as treatment for problem behavior maintained by automatic reinforcement. J Appl Behav Anal. 2019;52(1):299–314.

4.  Lumeij JT, Hommers CJ. Foraging ‘enrichment’ as treatment for pterotillomania. Appl Anim Behav Sci. 2008;111:85–94.

5.  Mellor EL, McDonald Kinkaid HK, Mendl MT, et al. Nature calls: intelligence and natural foraging style predict poor welfare in captive parrots. Proc Biol Sci. 2021;288(1960).

6.  van Zeeland YRA, Spruit BM, Rodenburg TB, et al. Feather damaging behaviour in parrots: a review with consideration of comparative aspects. Appl Anim Behav Sci. 2009;121:75–95.

7.  Kim LC, Garner JP, Millam JR. Preferences of orange-winged Amazon parrots (Amazona amazonica) for cage enrichment devices. Appl Anim Behav Sci. 2009;120:216–223.

8.  Webb NV, Famula TR, Millam JR. The effect of rope color, size and fray on environmental enrichment device interaction in male and female orange-winged Amazon parrots (Amazona amazonica). Appl Anim Behav Sci. 2010;124:149–156.

9.  Rozek JC, Millam JR. Preference and motivation for different diet forms and their effect on motivation for a foraging enrichment in captive orange-winged Amazon parrots (Amazona amazonica). Appl Anim Behav Sci. 2011;129:153–161.

10.  Gupfinger R, Kaltenbrunner M. The design of musical instruments for grey parrots: an artistic contribution toward auditory enrichment in the context of ACI. Multimodal Technol Interact. 2020;4(2):16.

11.  Alligood CA, Dorey NR, Mehrkam LR, Leighty KA. Applying behavior-analytic methodology to the science and practice of environmental enrichment in zoos and aquariums. Zoo Biol. 2017;36(3):175–185.

12.  Mettke-Hofmann C, Winkler H, Leisler B. The significance of ecological factors for exploration and neophobia in parrots. Ethol. 2002;108:249–272.

13.  Van Zeeland YRA, van der Aa MMJA, Vinke CM, Lumeij JT, Schoemaker NJ. Behavioural testing to determine differences between coping styles in grey parrots (Psittacus erithacus erithacus) with and without feather damaging behaviour. Appl Anim Behav Sci. 2013;148:218–231.

14.  Cussen VA, Mench JA. The relationship between personality dimensions and resiliency to environmental stress in orange-winged Amazon parrots (Amazona amazonica), as indicated by the development of abnormal behaviors. PLoS ONE. 2015;10(6).

15.  Fox RA, Millam JR. Novelty and individual differences influence neophobia in orange-winged Amazon parrots (Amazona amazonica). Appl Anim Behav Sci. 2007;104:107–115.