Avian Medicine: Avian Nutrition:
Nutri-Berries and Foraging:
A Neuroanatomic Perspective
Author: Susan E Orosz, PhD, DVM, Dipl. ABVP (Avian), Dipl. ECZM (Avian)
Date:February 12, 2010
Updated with additional references: November 24, 2010
Key words: Nutri-berries, foraging, enrichment, neuroanatomy, feather-damaging.
Key Points
- Brain studies point to environmental enrichment and foraging as important components of the natural conditions that continuously stimulate neurogenesis of the avian brain.
- Companion parrots carefully manipulate the multifaceted food item of Nutri-Berries and “feel” individual components with the side of their maxillary and mandibular bills and tongue.
- The rich textures and shapes stimulate many brain centers as they enhance the foraging experience.
- Brain studies suggest that the brain selects for situations that enhance neurogenesis and memory.
- Birds using Nutri-Berries, as a food source, have been observed to manipulate and work on this food item for longer periods of time compared with pellets.
- Companion parrots selecting Nutri-Berries over pellets in a home environment may be selecting for further brain stimulation.
The importance of foraging
Foraging for food is a basic behavioral repertoire for birds in the wild. The lack of opportunities for companion birds to engage in this behavior may play an important role in the development of abnormal behaviors. For example, Snyder et al documented that Puerto Rican Amazon parrots (Amazona vittata) spend approximately 4–6 hour per day foraging and that they routinely travel several miles between sites. In contrast, companion birds (orange-winged Amazons [Amazona amazonica]) in our homes spend approximately 30–72 minutes per day eating a pelleted diet without traveling, manipulating food items, and not attempting to balance their own diet (Oviatt, Meehan). It has been suggested that parrots in the wild may be highly motivated to forage and that this behavior is present in companion parrots as well. When foraging opportunities are not present, then abnormal behaviors may develop.
Orange-winged Amazon parrots that were parent-raised until weaning can develop feather-damaging behaviors (FDB) when placed into individual cages at weaning. Parrots in this study were divided into 2 groups, each receiving a daily ration of pellets in bowls. The first group was provided with physical enrichments, while the second group was given foraging enrichments along with their daily ration. Six of 8 parrots of the second group demonstrated an improved feather score, which suggests that enrichment allows for foraging and reduces FDB but does not eliminate it. This study also demonstrated that parrots in the enriched condition worked to access supplemental food items an average of 19–26% of their active time, even though their normal ration was available as a pellet.
The relationship between foraging and neural development
Foraging may be important for neural development in parrots. A strong relationship was also found between the lack of behavioral opportunity and the development of stereotypic behaviors in parrots, with evidence that there was an underlying neural compromise with stereotypy (Meehan). An environmentally induced neural dysfunction may underlie abnormal, repetitive behaviors.
Demanding foraging conditions affect the bird’s accuracy of retrieval of food items in caching species. Foraging was found to enhance memory in chickadees (Pravosudov). It is assumed that foraging stimulates the brain to improve memory in other avian species as well, as this would be an important behavioral trait in an ever-changing environment as food sources vary throughout the season.
Studies that were, in part, performed in birds have altered the neuroanatomic dogma that the number and complexity of its neurons does not change once the brain reaches adulthood (Gross). There are several locations in the brain that appear to undergo neurogenesis, including the dentate gyrus of the hippocampus of birds and mammals. These cell types are thought to be important in learning and memory.
Research on learning in birds
Starting in the late 1960’s, Nottebohm and his colleagues at Rockefeller University began a series of elegant experiments that explored the neural basis of song learning in birds. In these studies, Nottebohm and co-workers showed that there are thousands of cells that are added in the song learning areas and that these axons connect to structures vital to song — from production to quality. Development of these new neurons was generated, in part by seasonal hormone changes. Neuronal birth and death proceeded in parallel, both in singing and non-singing species. Neurogenesis was widespread throughout the avian forebrain — including the hippocampus, which was modulated by environmental complexity and learning experience (Adar, Nottebohm).
Brain studies point to environmental enrichment and foraging as important components of the natural conditions that continuously stimulate neurogenesis of the avian brain. It is likely that our companion birds need similar stimulation to fulfill these natural behavioral repertoires, and to stimulate brain neurogenesis and enhanced synaptic transmission.
Foraging involves searching for and manipulating food items and these same tasks can be actualized in a captive setting. Manipulation of the food item with the beak and tongue simulates sensory neurons in the bill and provides the brain with information relating to taste and texture. Cranial nerves V2,V3, VII, IX, and X provide sensory information along with size of item, taste, texture, and hardness to the brain, which causes these cranial nerve centers and their pathways to “light up”. Cranial nerve XII innervated the intrinsic muscles of the tongue for motor control and manipulation of the food.
Nutri-Berries
Nutri-Berries, due to their complex structure, provide varying textures and tastes within a single spherical product, unlike a pellet with its uniform shape and texture. The round shape and size of Nutri-Berries is comparable to what Amazons select for in the wild, as indicated in original studies by field biologist, Rodriguez-Vidal.
Companion parrots carefully manipulate the multifaceted food item of Nutri-Berries and “feel” individual components with the side of their maxillary and mandibular bills and tongue. The rich textures and shapes stimulate many brain centers as they enhance the foraging experience. Brain studies suggest that the brain selects for situations that enhance neurogenesis and memory. Birds using Nutri-Berries, as a food source, have been observed to manipulate and work on this food item for longer periods of time compared with pellets. The additional time spent consuming this food along with its advantage of complexity may be important factors in why birds tend to select for Nutri-Berries. At minimum, they stimulate a variety of cranial nerve nuclei (V, V3, VII,IX,X, and XII) and their pathways and may, as in experiments where foraging was enhanced, cause growth of the neurons within the dentate gyrus and improve memory along with other positive behavior changes. Companion parrots selecting Nutri-Berries over pellets in a home environment may be selecting for further brain stimulation.
Editor’s note:
References
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Gross CG. Neurogenesis in the adult brain: death of a dogma. Nature Reviews: Neuroscience 1(1):67–73, 2000.
Meehan CL, Millam JR, Mench JA. Foraging opportunity and increased physical complexity both prevent and reduce psychogenic feather picking by young Amazon parrots. Applied Anim Behav Sci 80(1):71–85, 2003.
Nottebohm F. In: Lakoski JM, Perez-Polo JR, Rossin DK (eds). Neural Control of Reproductive Function. New York, NY: AR Liss; 1989:538–601.
Nottebohm F. Neuronal replacement in adulthood. Ann NY Acad Sci 1457: 143–161, 1985.
Oviatt LA, Millam JR. Breeding behavior of captive orange-winged Amazon parrots.
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Pravosudov VV, Clayton NS. Effects of demanding foraging conditions on cache retrieval accuracy in food-caching mountain chickadees (Poecile gracili). Proc R Soc London B. 2001. 268:363–378.
Rodriguez-Vidal JA. Puerto Rican parrot study. Commonwealth of Puerto Rico, Dept. Agric. Mono. 1:15 p. 1959.
Snyder NFR, Wiley JW, Kepler CB. The Parrots of Luquillo: Natural History and Conservation of the Puerto Rican Parrot. Los Angeles , CA: The Western Foundation of Vertebrate Zoology; 1987.
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