Is The Secret to Saving Migratory Birds in the Meal Prep?



Sanderling Aldrin is one of the shorebirds being cared for by the Bird House team.

The Bird House team at the Smithsonian’s National Zoo has many beaks to feed, including 23 species of migratory songbirds and shorebirds (and growing!). But what happens when they are hungry to migrate and there’s nowhere to go? Curator Sara Hallager and nutritionist Erin Kendrick share some of the valuable lessons they have learned from taking these marvelous migrators under their wing.

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Gut-Loading Diet Evaluation for Crickets (Acheta domesticus), Mealworms (Tenebrio molitor), and Superworms (Zophobas morio) for the Purposes of Optimizing Institutional Protocols

For captive insectivorous birds, reptiles, and amphibians, gut-loading has become an essential part of a balanced diet when feeding commercial feeder insects. The captive bred crickets, mealworms, and superworms being fed have inadequate Ca and vitamin A to meet the nutritional needs of these animals. The trials conducted for this study were to determine which gut-loading diet would be the...

Body Condition Scoring Resource Center

  The following body condition scoring (BCS) scales have been obtained from a variety of sources.  We have credited the authors where we can, and encourage you to submit newly developed or modified scales or corrections to attributions.

The following body condition scoring (BCS) scales have been obtained from a variety of sources.  We have credited the authors where we can, and encourage you to submit newly developed or modified scales or corrections to attributions.

Click to expand

Pangolins, Aardvarks, & Xenarthrans (Sloths, Anteaters, Armadillos)

About BCS Scales

Body condition scoring (BCS) is a subjective measurement of an animal’s muscle definition and superficial fatty tissue.

BCS for Zoo Animals

BCS has been used for many years in the livestock industry to evaluate and improve the productivity, health, reproduction and longevity of herds.  BCS has become increasingly common in zoological settings for many of the same reasons.  Our greatest challenge in zoos is to develop practical systems or scales for the diverse species with which we work.  Some scales have been well-developed and validated, while others remain works in progress.  The NAG encourages the careful and thoughtful development of new scales, the refinement of those that already exist, and the diligent attention to their implementation for the good of the animals in our care.

About BCS Scales

Body condition scoring scales are numerical, and they typically range from 1 (emaciated) to either 5 or 9 (obese).  When using a 5-point scale, many people will assign half points (2.5 or 4.5 out of 5), which effectively turns the 5 point scale into a 9 point scale.  Whenever possible, we recommend the use of a 9 point scale.


Implications of BCS Scores


Low BCS scores have been associated with lowered reproductive success, poor recovery from illness, and may be a sign of disease or age.  High BCS scores have been associated with an increased risk of dystocia (difficulty giving birth), reproductive disorders, arthritis, diabetes, and other chronic conditions (Chan-McLeod et al. 1994; Burkholder 2000; Aeberhard et al. 2001; Busato et al. 2002; Berry et al. 2007; Boudreau 2012).  Despite the known risks of being too far at either end of the BCS spectrum, a BCS score should be non-judgmental.  You may be pleased that an animal recovering from a serious illness has moved from a 2 to a 3 (on a 9-pt scale), yet worry that a healthy animal has dropped from a 4 to a 3.  You may be glad that an obese animal has dropped from an 8 to a 5, yet endeavor to raise an animal preparing for hibernation from a 5 to an 8 or 9 (which may be “normal,” physiologically, for the species in question).  Keep in mind that just because it may be “normal” for a species to be over-conditioned at a specific time of year or life stage, this does not impact the BCS scale (a score of 8/9 remains 8/9, even if declared “appropriate” in terms of animal management; the scale does not “slide” to make that over-conditioned animal a 5/9). In addition, the scale is does not slide for growing, geriatric, or pregnant animals (regardless of stage of life, metabolic status, etc, the scale is designed to assess condition as objectively as possible).

Tips for Body Condition Scoring

  • BCS is best learned and implemented through consistent practice.  Often, it helps to have multiple staff involved at the start (animal managers, keepers, veterinarians, nutritionists, etc.) to make sure everyone is on the same page regarding terminology, anatomy, and the scoring system being used.  In the end, however, it is often best to have a limited number of scorers so that consistency can be maintained.  In addition, having someone who does not see the animals every day perform the scoring can be helpful.
  • Scorers should be familiar with the anatomy of each species.  If multiple scorers are utilized, they should be objectively evaluated for consistency with the same animals.  It can be helpful to note the initials of the scorer when a BCS is performed and recorded.
  • Although there are many different systems/scales (even for a single species), it is a good idea to pick one scoring system for each species and stick with it.  This allows for increased familiarity and proficiency, over time.
  • BCS is a particularly useful tool for animals that aren’t very tractable or for those who are unable to be weighed regularly.  If body weights are available, BCS acts as a complementary assessment for management purposes.  Ensure that the interval between BCS is reasonable and practical.
  • For growing animals, body weights can be paired with appropriate growth curves to assess development. However, body weights in growing individuals often vary, even within species, and may not be the best assessment of growth. In these cases, BCS can be used not only to assess appropriate growth, but also to establish target weights for individuals.

Developing BCS Scales

If your species of interest does not have a scale established, please consider developing one.  If you do, look at those that have already been thoughtfully developed.

Ideal BCS scales are easy to use, distinguish biologically relevant changes in status, provide enough description that multiple observers will obtain similar results, and, ideally, have been validated through other means (ultrasound, TOBEC, necropsy).  Photographs and drawings should clearly show points of interest and be coupled with clear written descriptions.   The NAG encourages you to share your systems by presenting a poster or presentation at our conference, or publishing in another format that can be accessed by the zoo community.

    • Aeberhard K, Bruckmaier RM, Kuepfer U, and Blum JW. 2001. Milk Yield and Composition, Nutrition, Body Conformation Traits, Body Condition Scores, Fertility and Diseases in High-Yielding Dairy Cows – Part 1. Journal of Veterinary Medicine Series A 48:97–110.
    • Berry DP, Lee JM, Macdonald KA, and Roche JR. 2007. Body Condition Score and Body Weight Effects on Dystocia and Stillbirths and Consequent Effects on Postcalving Performance. Journal of Dairy Science 90:4201–4211.
    • Boudreau L. 2012. Effect of Moderate Diet Restriction on Body Condition, Health, and Reproductive Performance in Female Mink (Neovison vison).
    • Burkholder WJ. 2000. Use of body condition scores in clinical assessment of the provision of optimal nutrition. Journal of the American Veterinary Medical Association 217:650–654.
    • Busato A, Faissler D, Küpfer U, and Blum JW. 2002. Body condition scores in dairy cows: associations with metabolic and endocrine changes in healthy dairy cows. Journal of Veterinary Medicine Series A 49:455–460.
  • Chan-McLeod ACA, White RG, and Holleman DF. 1994. Effects of protein and energy intake, body condition, and season on nutrient partitioning and milk production in caribou and reindeer. Canadian Journal of Zoology 72:938–947.

If you know of additional published resources for this page, we encourage you to submit them for potential inclusion:

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    Impact of dietary n-3 and n-6 PUFA on oxidative status and inflammation in yellow-rumped warblers

    The intake and ratio of the essential fatty acid classes, n-3 and n-6 polyunsaturated fatty acids (PUFA), impact animal health. The dietary ratio of these fatty acids can be important as n-3 PUFA are considered anti-inflammatory, while n-6 PUFA are pro-inflammatory. Additionally, the increased number of double bonds in PUFA makes them more vulnerable to oxidative damage, potentially increasing the...

    Evaluating the nutrition of a flock of non-breeding greater flamingos (Phoenicopterus ruber roseus) at the San Diego Zoo Safari Park

    A flock of 150 greater flamingos (Phoenicopterus ruber roseus) at the San Diego Zoo Safari Park were moved to a new enclosure in 2010 to provide them a larger exhibit and to promote the breeding of lesser flamingos (Phoeniconaias minor) that shared the previous exhibit. Since the greater flamingos moved, they have not laid eggs through June 2015. A nutrition...

    Nutritional and physical characteristics of commercial hand-feeding formulas for parrots

    Hand-rearing is a common practice for the propagation of psittacines, however, research on their nutrition is limited and the neonatal requirements are not well understood. We analyzed the nutrient composition and physical characteristics of 15 commercially available parrot handfeeding formulas. Formulas were compared with the average nutritional content of the crops of free living Scarlet Macaw (Ara macao) chicks. When the formulas were prepared...

    Growth curves and their implications in hand-rearing monk parrots (Myiopsitta monachus)

    Monk parrots (Myiopsitta monachus) were hand-reared over two chick seasons spanning from 2010-2011. Information on the growth curve of chicks hand-raised in 2010 was used to develop a feeding protocol for the 2011 season. This protocol was focused to address the problem areas of delayed growth and then excessive growth experienced by the baby parrots hand-reared in 2010. The 2011...

    Energetics and food needs of free-ranging wild mammals, birds, and reptiles

    The minimum metabolic rates (“basal” for endotherms and “standard” for ectotherms) of birds, mammals and reptiles are determined mainly by body size (mass), but that explanation may not work for field metabolic rates (FMR, or total daily energy requirement), which include additional energetic costs of activity, temperature regulation, foraging and food digestion, growth and reproduction, and social interactions, along with...

    Nutrition utilization by and diet preference of American white pelicans (Pelecanus erythrorhynchos) when offered diets of channel catfish and (or) grass carp

    Twelve pelicans (Pelecanus erythrorhynchos) captured in northeast Mississippi were used to determine nutrient metabolism when consuming channel catfish (Ictalurus punctatus) and(or) grass carp (Ctenopharyngodon idella). Another objective was to determine the dietary preference of pelicans when allowed to consume catfish and carp. For the 7-day metabolism trial pelicans were allotted to one of three treatment diets (4 birds/diet): catfish only,...

    The formulation of an artificial diet for captive kiwi (Apteryx mantelli)

    Population numbers of North Island brown kiwi (Apteryx mantelli) are estimated to have almost halved in the last decade. Despite some success of captive breeding, captive bred kiwi suffer higher embryonic and adult mortality rates, smaller eggs and lower hatching rates than wild kiwi. A major contributor to these problems is likely to be diet. The current diet fed to...

    Comparative crop milk composition in grantivorous and frugivorous Columbidae

    Crop milk, a glandular secretion produced by doves, pigeons, and some species of penguins and flamingoes, was collected from five different species of dove squabs at the Memphis Zoo between day 0 and 14 post-hatching. These species (Ptilinopus jambu, Ptilinopus magnificus, Gallicolumba luzonica, Gallicolumba rufigula, and Streptopelia decaocto), range from primarily frugivorous to primarily granivorous representatives of Columbidae. The samples...

    Differences in gut microflora between captive and wild birds: Are we getting the captive balance right?

    The microbiota of the vertebrate gastrointestinal tract consists of a diverse collection of microbial species. In the past, identification of these species has involved cultivation-based techniques. However, due to the dependence upon bacteria-specific media during cultivation, up to 80% of species may not have been identified using these techniques. To overcome this bias, a DNA-based technique of identifying microbial communities...

    Dietary treatment of iron storage disease in captive birds of paradise (Paradisaea raggiana)

    Elevated serum iron parameters were lowered through dietary manipulation in captive Bird of Paradise (Paradisaea raggiana) using a modification of previously published low-iron diets. Study birds were part of a captive breeding program consisting of two males and one female, captive born, 3.5 to 9 years of age. Serum iron, total iron binding capacity (TIBC), percent transferrin saturation, body weight,...

    So your director wants a farm in the zoo

    It seems that humans have always craved animal contact. Even at a zoo, a place designed for wild animals, visitors want and even expect to be able to touch an animal. Petting corrals, touch tanks, feeding stations, etc. are the most popular exhibits at a zoo, especially for families with young children. Contact areas can provide a valuable educational experience...

    A retrospective study evaluating vitamin E supplementation in pelicans and plasma alpha-tocopherol concentrations in pelicans, storks, and flamingos

    A retrospective study was conducted to evaluate the effectiveness of two vitamin E supplement forms in pink-backed pelicans (Pelecanus rufescens). The forms were a paste supplying 100 IU vitamin E daily or a capsule supplying 10.5 IU vitamin E daily. Baseline blood alpha-tocopherol concentrations were 7.15 ug/ml in 1998. After 10 months receiving vitamin E in the capsule form, the...

    Kori bustard nutrition and dietary husbandry

    Kori bustards (Ardeotis kori) are reported to be omnivorous, consuming mostly insect and plant material in their grassland habitat. A complete nutrient analysis of these food items and their contribution to the overall diet has not been determined. The gastrointestinal tract of the kori is typical of an insectivorous bird, but to date they have been fed in captivity as...


    In the spring of 2012, the Blank Park Zoo began suffering mortalities in a flock of 229 captive Budgerigars (Melopsittacus undulatus) housed in an interactive public-feeding aviary. Clinical signs included weakness, posterior paresis, inability to fly, central nervous signs or acute death. Gross and microscopic lesions were not apparent in acutely affected deceased birds. Many birds had evidence of trauma,...

    Modifying avian feeding strategies to provide foraging opportunity, allow for contrafreeloading and improve the health of collection birds

    The Philadelphia Zoological Gardens opened its gates to the public in 1874. At that time, zoo animals rarely survived more than several years in their captive environments. Little was known about the natural diet and behaviors of these wild animals, and keepers typically provided their charges with a variety of inappropriate food items. Nutrition programs for zoo animals simply did...


    Whenever possible, avian parents are tasked with raising their young. Occasionally circumstances dictate that young are pulled for hand rearing. Protocols are in place for different species that indicate food items and amounts to feed as well as developmental indicators and husbandry parameters. Avian species have different diets as adults but many utilize similar food items to feed their young....

    Voluntary intake by Hyacinth Macaws (Anodorhynchus hyacinthinus)

    In August 2004 two juvenile Hyacinth Macaws (Anodorhynchus hyacinthus) arrived at Temaikèn Wild Animal Park. Their feathers were in very bad condition and they weighed 1,230 g on average. At the very beginning, a diet with a great variety of ingredients was given. Two months later, during a first 5-day period leftovers were measured. At that moment the animals weighed...

    Effect of nutrition on the reproductive fitness of the endangered Attwater’s Prairie Chicken

    Attwater’s Prairie Chickens (Tympanuchus cupido attwateri) are an endangered Texan grouse species. Their survival relies on captive breeding for propagation of the free-ranging population. In recent years, chick hatchability and survivability in captivity has steadily decreased, with survivability in 2004 less than 30%. Preliminary data obtained in 2004 from captive and free ranging Attwater’s Prairie Chickens, demonstrated potential differences in...

    Preliminary efforts on hand-rearing three species of flamingos

    Between 2002 and 2005, the Fort Worth Zoo has hand-reared 37 flamingo chicks: nine Caribbean (Phoenicopterus ruber ruber), seventeen lesser (Phoeniconaias minor), and eleven Chilean (Phoenicopterus chilensis). The chicks were raised from hatching to the point of self-feeding. Body weight and formula consumption were measured daily. Feeding schedule transitions (from ten feedings per day to weaning) were based on body...

    Nutrient composition and dietary intake of captive horned guans (Oreophasis derbianus)

    Captive breeding successes of Oreophasis debianus, the horned guan, have been rare. The nutritional requirements of the species are unknown, and previous studies of its digestive physiology or captive nutritional husbandry have not been published. Three Mexican zoos with successful homed guan breeding programs were selected to evaluate dietary husbandry, including determination of nutrient composition of diets offered and consumed,...

    Growth rates and nutrient intake of hand-rearing pink-backed pelicans (Pelecanus rufescens) at Disney’s Animal Kingdom Lodge

    Between December 18, 2006 and February 12, 2007, four pink-backed pelican (Pelecanus rufescens) chicks were hatched and hand reared at Disney’s Animal Kingdom (DAK). A pelican hand rearing protocol was developed based on that of the San Diego Zoological Society. The diet was designed to consist of combinations of capelin, smelt, sardines and herring, along with a vitamin and mineral...

    Are super dose concentrations of vitamin E really necessary for reproduction in birds?

    Vitamin E requirements for exotic avian species remain undetermined and await investigation. As a result, diets formulated for captive exotic birds rely on the development of target ranges and feeding guidelines in order to minimize the risk of developing deficiencies and/or toxicities. These target ranges are commonly based on the requirements of domestic poultry, with the addition of calculation factors...

    Columbiform crop milk and crop milk replacer

    Altricial chicks undergo an intense period of growth in the first few weeks of life. These chicks’ huge needs for nutrients are usually met by their parents feeding them high protein food items such as insects, other invertebrates, or vertebrate prey. Columbiformes (doves and pigeons) have conquered this nutritional obstacle a different way, by manufacturing the perfect food for their...

    Training, enrichment and sound animal nutrition can coexist the development of a multifaceted bird feeding program at the Philadelphia Zoo

    In conjunction with the development of a new training program, the Zoo developed a 4 part-feeding program for collection birds that integrates training with nutrition and enrichment. This program allowed the Zoo to better monitor the feed intake of individual birds within a mixed species exhibit and collect data on individual animals. The program placed birds into three general groupings...