Contributing Authors: Mélanie Ammersbach1 DVM | Hugues Beaufrère2 DVM, PhD, ABVP (Avian), ECZM (Avian) Annick Gionet Rollick3 BSc | Brent Hoff1 DVM, DVSc, Dip Tox 1 Department of Pathobiology and Animal Health Laboratory, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada 2 Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, U.S.A 3 The Owl Foundation, Vineland Station, Ontario, Canada contributing author s wls are represented throughout 6 of the 7 wildlife veterinarians and rehabilitators. Furthermore, continents, with 205 species split into two a great number of owl species are kept in captivity in distinct families; Tytonidae (16 species) and zoological institutions and for education programs. Strigidae (189 species). They range in size from Othe smallest, the Elf Owl at just 16 cm (40g) to the largest, the Eurasian Eagle Owl at 71 cm (4800g). As top predators they are useful as bio-indicators to evaluate ecosystem health. The International Union for Conservation of Nature and Natural Resources states 31% (based on 186 species) of those listed are categorized as a species of concern in need of protection and continued study and evaluation.

With the exponentially decreasing natural world, owls are finding themselves ever closer to human habitation. Some species have managed to co-exist in the urban sprawl while others struggle to grab hold of a niche, often falling ill from injury, starvation and competition for space. The rapidity of change in their environment makes adaptation a challenge. A thorough health check including a Some of the species included in the physical examination by the staff of the Owl study were small and so the blood For some species of owls, their only chance for a stable Foundation and Avian Veterinarian Hugues volume was small like in this ~ 80g population is through captive breeding and re-introduction Beaufrere was performed on the captive or Northern Saw-whet Owl (Aegolius pre-released owls to ensure that they are acadicus). Luckily, only 2 drops are programs. For others, a second chance to propagate in the healthy prior to sampling. needed to perform a full biochemistry wild through rehabilitation brings them into the hands of using the VetScan.

Volume 52 | Vetcom | 23 Normal Hematologic P arameters on Eleven Species of Owls

While hematologic and biochemical information exist All owls were fasted for a minimum of 12 hours prior to for birds of prey, they are mainly available for diurnal sampling to prevent lipemia and post-prandial elevations raptors of the falconiformes (falcons) and accipitriformes in uric acid. The plasma was separated within 4 hours after (hawks, eagles) orders. However, there is currently a lack of blood collection to prevent changes in glucose, lactate hematological reference data in owls to assist in the treatment dehydrogenase and electrolytes in vitro. The samples were of illness or injury and for use in preventative medicine frozen at -20ºC until the biochemistry analysis using the practices to monitor owls placed in captivity. Strigiformes Avian/Reptilian Profile Plus rotors in a Vetscan VS2. Blood are not related to other birds of prey and have completely biochemistries were also performed on the Cobas 501 to different lifestyle and some physiological peculiarities. Thus perform an agreement analysis with the VS2, and a manual group-specific reference intervals are needed to increase the complete blood count was performed using 3 different value of blood test and their interpretation. techniques (Phloxine stain, Natt and Harrick solution, and estimation from the smear) to obtain the total leukocyte count.

We are very grateful to Abaxis for donating Avian/Reptilian profile rotors for this project and the Animal Health Laboratory for allowing us to use their VS2 and Cobas 501. We hope that the results of this study will help improve the health and medical care of owls kept in captivity in rehabilitation centers and zoological institutions. We would also like to thank The Owl Foundation, The Mountsberg Conservation Center, The Toronto Wildlife Center and The Toronto Zoo and their staff for assisting us with blood collection from their healthy captive or pre-release owls.

Blood sampling from the left jugular vein The fat distribution pattern and weight of of a Snowy Owl (Bubo scandiacus). (head the birds are monitored as part of the health down, facing to the left) check.

The Vetscan Avian/Reptile profile provides a unique opportunity to perform a full plasma biochemical panel on a small blood volume. The Vetscan is also easy to use and is a common benchtop laboratory analyzer in rehabilitation and zoological settings. In order to determine biochemical reference values in owl species, Abaxis donated rotors to a joint scientific project between the University of Guelph and Louisiana State University on strigiformes hematology.

Blood samples were collected on close to 120 healthy releasable or captive owls from different centers, primarily from The Owl Foundation but also from the Mountsberg Conservation Area, the Toronto Wildlife Center and the Toronto Zoo. The species enrolled included European eagle owls (Bubo bubo), barred owls (Strix varia), great horned owl (Bubo virginianus), barn owl (Tyto alba), great gray owl (Strix laponica), eastern screech owl (Megascops asio), snowy owl (Bubo scandiacus), short-eared owl Asio flammeus Aegolius acadicus s author contributing ( ), saw-whet owl ( ), long- eared owl (Asio otus), and Northern hawk owl (Surnia ulula). The study is ongoing and more birds will continue to be recruited. Our goal is to collect a minimum of 20 individuals per species so that species-specific reference intervals can be established and compared with one another. Great Horned Owl (Bubo virginianus)

24 | Vetcom | Volume 52 Normal Hematologic P arameters on Eleven Species of Owls

Snowy Owl (Bubo scandiacus) Snowy Owl (Bubo scandiacus) Two Great Grey Owls

Preliminary reference intervals for the Vetscan plasma biochemistry profile in the order strigiformes (SI units). Calculated using a non-parametric method. N, sample size; RI, reference interval. Values are reported with the measurement precision of the Vetscan. N Median RI

Ca (mmol/L) 100 2.29 1.32-2.85 Phos (mmol/L) 100 1.11 0.34-2.23 Na (mmol/L) 99 151 138-165 K (mmol/L) 100 4.4 1.7-6.6 TP (mmol/L) 100 38 30-48 Albumin (g/L) 100 31 21-47 Globulin (g/L) 100 5 0-22

Glucose (mmol/L) 100 18.7 11.7-25.1 contributing author s AST (IU/L) 100 207 104-410 CK (IU/L) 98 249 0-3169 Uric acid (µmol/L) 99 408 175-993 Bile acids (mmol/L) 99 <35 <35

Preliminary reference intervals for hematologic parameters in the order strigiformes. Calculated using a non-parametric method. N, sample size; RI, reference interval; PCV, packed cell volume; TS, total solids; RBC, red blood cell count; WBC, white blood cell count. NB/ RI are order-specific and not species-specific and are expected to be wider than species-specific RI.

N Median RI

PCV (%) 131 48.0 35.4-61.6 TS (g/L) 136 42.0 36-61 RBC (x 1012/L) 185 2.6 1.3-4.1 WBC (x 109/L) 159 11.5 2.1-28.3 Heterophils (x 109/L) 159 4.3 0.6-15.6 Lymphocytes (x 109/L) 159 2.6 0.3-12.5 Monocytes (x 109/L) 159 0.9 0.1-4.3 Eosinophils (x 109/L) 159 1.2 0.1-6.3 Basophils (x 109/L) 159 0.2 0.0-1.2

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