- Foraging makes up a significant part of the wild parrot’s day.
- Captive parrots are motivated to forage, too.
- Thwarting the ability to forage may be detrimental to the parrot.
- Foraging enrichment offers many benefits.
- Foraging opportunities are endless, but may differ in their effect.
Adapted from van Zeeland YRA, Schoemaker NJ, Ravesteijn MM, et al. Efficacy of foraging enrichments to increase foraging time in Grey parrots (Psittacus erithacus erithacus). Applied Animal Behaviour Science 149:87-102, 2013.
The wild parrot’s day
Foraging is the act of searching for, finding, and procuring food. In the wild, most animals, including psittacine birds, spend a significant part of their daily activity on foraging. In fact, many free-ranging parrots regularly travel several miles between feeding sites in search of food (Symes 2003, Wirminghaus 2001, Gilardi 1998, Synder 1987). Once free-ranging parrots arrive at a feeding site, a wide variety of foraging behaviors are observed including searching, selecting and obtaining, manipulating, as well as consuming food (Synder 1987). Foraging makes up a significant part of the wild bird’s day (Fig 1). Depending on the species and the season, time invested on these behaviors can range from 40% to 75% of daytime or approximately 4 to 8 hours per day (Renton 2001, Sydner 1987, Magrath 1985).
Most parrots kept in captivity should be considered as non-domesticated species, being only one or two generations removed from the wild. Therefore the instincts, behaviors, and needs of captive parrots are probably similar to those of their wild conspecifics (Davis 1998, Graham 1998). It would thus be likely that captive parrots have a need to forage, too.
Previous studies have provided evidence in support of the hypothesis that foraging is a behavioral need by demonstrating that parrots are motivated to work for food (Joseph 2010, van Zeeland 2009, Coulton 1997). Similar to other animals, parrots would choose to work for food even when identical food is freely available. This behavior is also known as “contrafreeloading” (Video 1).
Video 1. View this example of contrafreeloading in psittacine birds (1:01). Note: This video is the property of Dr. Yvonne R.A. van Zeeland and the Division of Zoological Medicine, Faculty of Veterinary Medicine, Utrecht University, the Netherlands, and cannot be downloaded or used without permission.
When parrots cannot forage
In the conventional captive parrot environment, food is often offered in a regular food bowl from which it may be readily consumed by the parrot thereby resulting in foraging times of less than an hour (Oviatt and Millam 1997; Rozek et al 2010; van Zeeland 2013). This leaves little room for the parrots to display their natural foraging activities. As a consequence, abnormal repetitive behaviors can arise including oral stereotypies, such as wire chewing or tongue playing, and feather destructive behavior (Fig 2) (Lumeij 2008, Meehan 2004, Meehan 2003, Huber-Eicher 1998).
The benefits of foraging
Foraging enrichment is considered one of the most effective strategies to improve welfare and reduce behavioral problems in captive animals including parrots (Dixon 2010, Lumeij 2008, Miller 2005, Meehan 2004, Meehan 2003, Elson 2001, Coulton 1997, van Hoek 1997). Foraging increases physical activity, provides cognitive stimulation, relieves stress, frustration, or boredom while reducing and preventing aggression and abnormal repetitive behaviors including stereotypies (Box 1) (Brinch-Riber 2008, Vargas-Ashby 2007, Aerni 2000).
|Box 1. Benefits of foraging (Brinch-Riber 2008, Vargas-Ashby 2007, Aerni 2000)|
Several approaches have been developed to stimulate foraging behavior and increase foraging times in a variety of species ranging from megavertebrates to reptiles (van Krimpen 2009, Aerni 2000, Bauck 1998, Newberry 1995):
- Multiple bowls to offer smaller, more frequent meals in multiple locations
- Mix food with inedible items
- Increase feeding time by offering vegetation, bones, ice blocks, whole food item, carcasses, etc.
- Foraging devices (puzzle feeders)
- Scatter or hide food in enclosure
- Live prey (in predatory animals)
- Increase dietary fiber (promote satiety)
- Feed at irregular time intervals to decrease the predictability of feeding times
Although many studies have been performed into the efficacy of foraging enrichment on normal and abnormal behavior in various species, most of these offered multiple types of foraging enrichment at once, thereby making it difficult to evaluate the relative merit of each individual technique.
In search of the perfect foraging enrichment
In our study, the following foraging enrichment techniques were evaluated in 12 grey parrots (Psittacus erithacus) (van Zeeland 2013):
- Increasing the spatial distribution of food within the enclosure: Pellets were placed in four food bowls rather than one location. Two bowls were hung at the level of the highest perch and two were placed on ground level on opposite ends of the cage.
- Increase search time by mixing food with inedible items: Food items offered to grey parrots were mixed with marbles measuring 1.5 cm in diameter.
- Increase extraction time: Foraging devices or puzzle tend to remain stimulating to the animal, especially when they contain the individual’s total daily diet (Lumeij 2008, Shyne 2006, Bauck 1998, Coulton 1997). Eight different devices were evaluated.
- Increase the time needed to process and ingest food: Lafeber Company Nutri-Berries were offered as an example of a larger-sized food particle. This nutritionally balanced mix of seeds, grains, nuts, and pellets is shaped into the form of a berry measuring 2.5 cm in diameter (Fig 3).
After acclimatization and assessment of baseline foraging times, enrichments were presented in a random order. Enrichments were gradually introduced, and video recordings were used to analyze total foraging time as well as the time spent on different foraging activities. The frequency and duration of foraging periods and the times at which they occurred were also determined.
In addition, learning curves and familiarization with enrichment items were assessed over a 1-week period. Differences in learning curves were most likely due to differences in the difficulty level of enrichments. Parrots needed 8.3 +/- 1.1 days to learn how to use the foraging enrichments. For two puzzle feeders, it took considerably longer. Parrots in this study needed little to no time to learn how to use Nutri-Berries; they only needed to learn where food was located and no further effort was required to obtain food.
How effectively can foraging enrichments increase foraging times?
Our study investigated the effects of different types of enrichment on foraging times and foraging-related activities in grey parrots (Box 2) (van Zeeland 2013).
|Box 2. Hypothesis (van Zeeland 2013)|
|Although all types of foraging enrichment would result in significant increases of foraging times compared to baseline values, puzzle feeders would result in the highest increases in foraging times.|
The parrots in our study spent an average 47 + 18 min per day on foraging activities when offered a conventional pelleted diet in a regular bowl. These baseline values are similar to those reported in Amazon parrots (Rozek 2010, Oviatt 1997). Foraging enrichments could indeed increase foraging times, and nine out of 11 foraging enrichments significantly increased foraging times in the grey parrots studied.
- The most effective enrichments resulted in a 2- to 2.5-fold increase compared to baseline. The most effective enrichments were three different puzzle feeders, which increased foraging time up to 123 + 52 min (Fig 4 and Fig 5).
- The effect of Nutri-Berries was comparable to the most effective puzzle feeders, resulting in foraging times that exceeded 100 minutes per day. This increase in foraging time was similar but less to that compared to the feeding of larger-sized pellets by Rozek 2010. As both food items were similar size in size (approximately 2.5 cm diameter) other factors such as hardness, structure, nutritional composition, and/or energy content may have contributed to this difference.
- The least effective foraging enrichments were two foraging devices as well as food placement in multiple locations. This latter technique has been shown to be most effective in parrots housed in a large enclosure or aviary (Elson 2001, Coulton 1997, van Hoek 1997), and the results of our study seem to support this finding (van Zeeland 2013).
Considerations for the future
The results of this study (van Zeeland 2013) will help make evidence-based decisions on best way to provide foraging enrichment to grey parrots. Approaches that focus on increasing extraction time by using puzzle feeders and increasing food processing time with larger-sized food particles such as Nutri-Berries appear to be most effective in increasing foraging time.
Thus far the maximum foraging times that have been obtained in captive parrots provided with foraging enrichment have not exceeded 3 hours per day (Rozek 2010, Lumeij 2008, Elson 2001). To further increase foraging times in captive parrots, new more effective foraging and currently available foraging enrichments should be developed, tested, and refined, during which individual preferences for specific colors, sizes, hardness and/or structure (as demonstrated in studies by Rozek 2011, Webb 2010, Kim 2009, Fox 2007) should also be taken into account. As preferences may differ between genders, ages, and/or species, these should be further studied to be able to adapt the enrichment to the needs and preferences of the bird.
Dr. van Zeeland’s thesis can be downloaded for free from dspace library or contact Dr. van Zeeland to order a printed copy, which includes a special cover with a lenticular image of a grey parrot that either has its feathers plucked or is normally feathered (Fig 6).
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