Growth patterns in Barbary partridges Alectoris barbara originated from low- and high elevations in West central Morocco

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1 Avocetta 38: (214) Growth patterns in Barbary partridges Alectoris barbara originated ro low- and high elevations in West central Morocco Mohaed Aourir 1 *, Abdelilah El Abbassi 2, Mohaed Znari 2 1 Departeent o Biology, Faculty o Sciences, Ibn Zohr University - PO Box 816, Agadir, Morocco. 2 Laboratory Biodiversité et dynaique des écosystèes, Departent o Biology, Faculty o Sciences, Cadi Ayyad U- ni versity - PO Box 239, Marrakech 4, Morocco. *Corresponding author: aourir@gail.co Abstract The Barbary partridge, the aily Phasianidae, is the ain gae bird in Morocco and which was reported to be heavier and larger in ountains than in lowlands. In this regard, the purpose o the present study was to investigate posthatching growth o body weight and seven orphoetric paraeters in Barbary partridges Alectoris barbara originated ro low- and high elevations, and raised in coon captive environent. Gopertz odel presents the best it to the growth curves or body weight, wing, leg and sternu. Mean body weight at hatching was siilar between elevations and was relatively higher, copared to that in other studied perdicine species. Adult Barbary partridges ro high and low elevations aintained the dierence in body weight when raised in coon captive environent. This suggests a role o genetic selection and / or aternal eects between the two studied populations. However, all the other growth paraeters o orphological traits were siilar between captive birds originated ro the two elevations. This lack o dierence could be related to a potential phenotypic plasticity with a convergence in coon captive environent. Key-words: Barbary partridge; body weight; growth rate; orphoetry; ountains; plain. INTRODUCTION Barbary partridge Alectoris barbara is wildly distributed predoinantly in North Arica ro Morocco to Egypt, but also occurs in the Canary Islands, Gibraltar and Sardinia (Crap & Sions 198, Madge & Gowan 22). Over uch o its range, it has declined due to hunting pressure and habitat degradation (Madge & Gowan 22, BirdLie International 24). It is locally nuerous in Morocco, Algeria and Tunisia, and its current status in Libya is unknown and it is perhaps extinct in Egypt (Madge & Gowan 22). Although the Barbary partridge is the ain gae bird species in North Arica, little research have been conducted on its biology and ecology. Previous investigations were carried out on soe aspects o osoregulation (Hollander 1971), reproductive ecology (Alaoui 1992, 21, Akil & Boudedja 21) and ore recently on parasitology (Foronda et al. 25). Ephasis on Barbary partridge breeding in captivity is growing due its econoic value or coercial production (gae bird, gae bird, eat production), its ecological iportance with protection o wild. However, no 214 CISO - Centro Italiano Studi Ornitologici growth patterns investigation have so ar been perored in North Arican populations. The orphological growth is one o the undaental aspects in the study o biology and lie history o birds. The growth act is under control o genetic and environental conditions in living organiss (Barbato 1991). Research in this area (see Rickles 1973, O Connor 1984, Stark & Rickles 1998 or review), have characterized quantitatively the patterns o developent and thus acilitated analysis and coparisons. Suicient inoration on growth paraeters could be used easily at breeding and genetic selection studies, deterining attening period and eeding strategy econoically. Based on ean adult body weight, hunted Moroccan Barbary partridges o both sexes in high altitude (High Atlas ountains, 19 a.s.l.) revealed to be larger and heavier than those ro lowlands (Northwest Morocco, 5 a.s.l.), and have been suggested as a distinct race (Alaoui 21). Assuing that constraints in growth are acilitated when birds are raised in the sae captive conditions, orphological traits o birds originated ro dierent elevations, ay change in a nuber o ways when reared in coon aviary environent 45

2 Aourir et al. (see Bears et al. 28). So, in the present work, we tested whether the dierence in growth paraeters between low- and high elevation populations o Barbary partridge, is aintained in aviary and i so, to see i the corresponding growth patterns are also distinct. For this purpose, we analyzed and odeled postnatal growth patterns o body weight and length o the wing, sternu and leg in Barbary partridge originated ro lowlands and ountains o west central Morocco, hatched and raised under identical environental captive conditions. MATERIALS AND METHODS Egg origin and incubation Birds used in the present work originated ro eggs collected (under licence) in the wild during the breeding season (April 26), in two dierent sites in the region o Marrakech (Morocco). 12 eggs taken ro two nests at 24 o altitude in Ouirgane Reserve (High Atlas Mountain) and 11 eggs harvested ro two nests in the Haouz plain at Taazouzt area (54 o altitude). Eggs were individually arked and artiicially incubated in an air-orced incubator (T = 38.3 C). When eggs started piping, they were transerred into a hatcher set at 7% huidity within the incubator where chicks are let to dry or 5-6 hr. Maintenance conditions and easureents Ater hatching, chicks were individually arked with colored plastic rings and housed together in brooders (5 x 5 x 3 c), equipped with an inra- red lap (6 watts). This provides a theral gradient ro 38 ± 2 C under the heater to 25 ± 2 C at the periphery o the brooder allowing the chicks to select the suitable air teperature (Ogilvie 197). Ater 7 days, chicks were oved into siilar larger brooders (12x8x6 c) with sand and very sall gravels as substrate to stiulate locootion. Fro a iniu age o three weeks, the birds have been ringed (nubered aluinu rings) and then transerred to spacious in-roo cages (15 x 12 x 7c). The photoperiod was autoatically set to 14L : 1D. Poultry pellets (~18% o protein and 1.5% calciu, 1% phosphorus and vitains A, D, E) oered in trays ro 1 to 15d and a grower diet (25% o protein) with a ixture o seeds (wheat, illet, groats, wild ustard seeds, and lentils) ro 16 d. Food and water were provided ad libitu. During the whole study, growing partridges were aintained in a ventilated air-conditioned roo (T = 25 ± 1 C and RH = 4 ± 1%). Sub-adults were housed in an outdoor aviary set (1 x 5 x 2.5 ) ro an age o 1-12 weeks. The body weight (g) was deterined to the nearest.1 g using an electronic balance (AND HL-4). The orphoetric easureents were ade using a caliper (Calab) to.1, during the juvenile period ro hatching until the age o an adult size 21 individuals. Seven orphoetric paraeters, were easured: length o the wing (upper wing, lower wing and hand), the sternu, and length o the leg (upper leg, lower leg and tarsus). All easureents were carried out between 7-9 p.., daily until the age o 3 days and then every 2-5 days until the age o 6 days and then every 5 to 1 days until the age o 12 days. Sexing o the studied birds was ade a posteriori, using the only visible sexual diorphic character, naely spurs present in adult ales ro an age o weeks, and conired by observing the socio-sexual behavior during the breeding season. Data treatent and statistics The Growth paraeters were deterined by itting growth curve data to the two coon applied growth equations or birds (Rickles 1973): (1) Gopertz: W t = A.exp (-exp (-K (t-t i )); (2) logistic: W t = A/(1+exp (-K (t-t i )). Where W t represents size at tie t (days), A is asyptote value, t i (d) is the age at the inlection point, and K is growth constant rate (d -1 ). Growth curve its were perored using Curve Expert 1.3 (25). In order to choose the atheatical odel, which gives the best it between the equation and all easureents, we copared reduced Chi square or the tested growth odels; reduced Chi square o approxiately 1 is indicative o a good adjustent. Nuerous coparisons were done using the general odels procedure to test or eect o sex on each variable. Means were copared using Fisher test (F-test) or t-student test with signiicance thresholds α =.5. RESULTS Body weight and easureents data were obtained on 21 chicks including 1 ales and 11 eales originated ro the plain or ountains. The Gopertz growth odel provided the best it or all easureents (with highest deterination coeicient and the lowest residual variance) as copared to logistic odel. Also, we considered the Gopertz equation or describing the growth o all the variables studied. Body weight growth paraeters The general pattern o daily growth in Barbara partridge was sigoid or body weight (Fig. 1). Estiates o the paraeters A, K G and t i predicted by the Gopertz equation, are given in Table 1. Body weight at hatching was 46

3 Barbary partridge growth patterns Table 1. Mean values o growth paraeters or body weight in Barbary partridge originated ro the plain and ountains. Sexe N W h A K G t i r 2 Males Feales ± ±.95 * ± * ± ± ± ± ± ± ±.13 N: nuber o individuals; W h : Body weight at hatching (g); A: Asyptotic body weight (g); K G : Growth rate (d -1 ); t i : Inlection point (d); *: P <.5. not signiicantly dierent between ales and eales (P >.5) and was average respectively o ±.97 g, (N = 1) and 15.1 ±.95 g, (N = 11) and siilar between elevations in both sexes. This represents about 3.2% o the breeding eale ean asyptotic body weight ( ± g, N = 11). Sexual diorphis in body size was observed at the end o the growing period, with ales being signiicantly heavier than eales ( ± vs ± g) (P <.5) (Table 1). The growth rate constant (K G ), age at axiu growth (t i ), predicted by the Gopertz equation were respectively.357 ±.3 d -1 and ± 2.9 d or ales and.344 ±.25 d -1 and ± 4.37 d or eales. Except or the asyptotic body weight, the other growth paraeters in both sexes o the Barbary partridge does not account or a signiicant eect (P >.5) (Table 1). The growth rate constant (K G ) and the inlection point (t i ) averaged o.35 ±.2 d -1 and o 37 ± 1.9 d -1 respectively. Morphoetric growth paraeters As or body weight, the general pattern o daily growth in Barbary partridge was sigoid or all the seven-orphoetric paraeters studied (Fig. 2). No signiicant dierences were detected between sexes or all orphoetric paraeters o the wing, the leg and the sternu (P >.5 in all cases). The respective absolute total lengths o wing (ar + orear + hand), sternu and leg (eur + tibia + tarsus), at hatching averaged 38.2 ± 2.1, 1.6 ± 1.13 and ± 1.8 respectively. The ean growth rates (K G ) o the wing and sternu are relatively higher (.46 ±.4 d -1 and.44 ±.3 d -1 respectively), than that o the leg (.33 ±.9 d -1 ) (Table 3). In both sexes, the ean o the age at axiu growth (t i ) o the lower wing, upper wing and upper leg are reach aster (9.23 ± 1.9 d) than or the hand, lower leg (36.53 ± 1.47 and ± 1.98 d respectively) (Table 2). Intra-speciic growth coparison: Plain vs. Mountain Partridges ro the ountain have an asyptotic body weight higher than those ro the plain, and this dierence is uch ore signiicant in the case o ales ( ± g vs ± g) (P <.1) than in eales ( ± g vs ± g) (P <.5) (Table 3). Males ro ountain and plain have a body weight growth rate higher than that o eales (.37 ±.3 g and.36 ±,3 g vs..33 ±.1 g and,33 ±,1 g respectively) (P <.1) (Table 3). 5 Body weight (g) Mountain (Feale) Mountain (Male) Plain (Feale) Plain (Male) Age (day) Figure 1. Growth curves o body weight as a unction o age in Barbary partridge itted to the Gopertz equation. 47

4 Aourir et al. Table 2. Mean values o orphoetric growth paraeters estiated or Gopertz odel in Barbary partridge originated ro the plain and ountains. Data are eans o 1 ales and 11 eales. Sexe A K t i r 2 G Hand ± ± ± ± ± ± ± ±.8 Lower wing ± ± ± ± ± ± ± ±.146 Upper wing ± ± ± ± ± ± ± ±.41 Sternu ± ± ± ± ± ± ± ±.113 Upper leg ± ± ± ± ± ± ± ±.152 Lower leg ± ± ±.5.35 ± ± ± ± ±.4 Tarsus ± ± ± ± ± ± ± ±.1 L h : Length at hatching (g); A: Asyptotic length (g); K G : Growth rate in (d -1 ); t i : Inlection point (d); r 2 : coeicient o deterination; : ales and : eales. DISCUSSION Except or the asyptotic body weight, there were no signiicant dierences in all the other growth paraeters (including all orphological paraeters) between the two studied populations ro low- and high elevations in West-central Morocco. So, the asyptotic body weight and the other growth paraeters are here discussed respectively at intra- and inter-speciic levels. Inter-speciic coparison Although postnatal growth has been investigated in several gallinaceous species (see Starck & Sutter 2 and reerences therein), there are relatively ew data on wild perdicine phasianids. In a copilation by Starck & Sutter (2), data were provided only or rock partridges Alectoris graeca, grey partridges Perdix perdix and the Japanese quail Coturnix cortunix. More recently, Pis (212) reported data on growth paraeters o the body weight, tarsus, wing and bill lengths in chukar Alectoris chukar and grey partridges. As a typical precocial land species, Barbary partridge chicks hatched with relatively well developed body weight (15.1 ±.9 g: 3.2% asyptotic body weight), coparatively with chukar and grey partridge chicks 12.5 g and 9.6 g ( % asyptotic body weight), respectively (Pis 212). The Barbary partridge adult body weight (~ 46 g) was interediate between grey partridges (382 g) and chukars (523 g) (Pis 212). Based on data or 14 perdicine species (Starck & Sutter 2, Pis 212), the Gopertz growth rate (K G, d -1 ) or the body weight is ound to be alloetrically and signiicantly related to the asyptotic body weight (A, g) according to the ollowing equation: K G =.526*A -,416, r 2 =.758. The Gopertz growth rate corrected or asyptotic body weight (K G = K G /A -,416 ) in the Barbary partridge revealed to be relatively lower than those calculated or the grey partridge and chukar (.447 vs..458 and.516). The slower growth rate observed in Barbary partridge chicks could be attributed to their wild origin copared to the two other species which were probably accliated to captive conditions and bred or several generations in Western Poland (Pis 212). In this regard, the investigations o the relation between growth rate and aturation o skeletal uscles over a size range o gallior birds by Dietz & Rickles (1997), showed that the slower growth ay reduce daily energy and nutrient requireents, allowing chicks to subsist on lower quality diets and providing greater saety argins in case o decrease in ood supply. Adult ales o Barbary partridge are signiicantly heavier than adult eales; this ale-biased sexual diorphis in asyptotic body size, oten plays a role in intrasexual copetition with larger ales probably being avoured in territorial contexts. The locootory systes o Barbary partridge are suiciently developed to enable chicks to ove in their envi- 48

5 Barbary partridge growth patterns 2 16 WING Lenght () STERNUM Lenght () 6 Mountain (Feale) Mountain (Male) Plain (Feale) 4 Plain (Male) LEG Lenght () Age (day) Figure 2. Growth curves o wing, sternu and leg lengths as a unction o age in Barbary partridge itted to the Gopertz equation. 49

6 Aourir et al. Table 3. Eect o the egg origin and sexes on the growth paraeters or body weight in the Barbary partridge. N W h A K G t i Males Plain Mountain ± ± ± 4.85 ***51.96 ± ±.1 *.37 ± Feales Plain Mountain ± ± ± * ± ±.1 *.36 ± N: nuber o individuals; W h : Body weight at hatching (g); A: Asyptotic weight (g); K G : Growth rate (d -1 ); t i : Inlection point (d); *: P <.5; ***: P <.5. ronent. Ater hatching, the upper and lower wing and the upper leg grow aster than the tarsus and low leg (t i = 1 vs. 25 d). The general pattern and ode o developent o the locootory systes in this species are closely adapted to their ecological circustances during the pre-ledging period. The ast growth o the upper legs and the wings ten days ater hatching increases the obility o chicks and thus iprove their chance o escaping potential predators whilst unable to ly and allow the chick to pass ore quickly through the vulnerable developent period. Captive Barbary partridge chicks can ledge at about three to our weeks ater hatching, when attaining only 33% o adult body weight. On the other hand, Barbary partridge chicks hatch with well-developed legs to enable chicks to ove in the exposed open environents and to eed theselves ro their irst day on insects and then seeds and other plant aterials. In growing birds, resources are allocated preerentially to growth o the coponent with the highest current unctional priority, with due regard or uture needs (O Connor 1984). Rickles (1979) has discussed the signiicance o highly developed legs at hatching, which he attributed to the need or hooeotheric capacity because leg uscles are the ost iportant source o heat production early in a chick s lie. Meanwhile, the growth o sternu becoes aster three weeks ater hatching in relation with an iportant developent o breast uscles necessary or ledgling. Adult Barbary partridges which were reported as heavier in high elevation than in low elevation, aintained this dierence in body weight when raised in coon captive environent. This suggests a role o genetic selection and/or aternal eects between the two studied populations. On the other hand, all the other orphological traits and related growth paraeters were siilar between captive birds originated ro the two elevations. This lack o dierence could be related to a genetic siilarity between populations or a phenotypic plasticity with a convergence in coon captive environent. Coparatively to other studied perdicine species, Barbary partridge, regardless to its environental origin, hatch at a higher body weight, but with a lower growth rate or a siilar asyptotic body weight. The locootory syste develops aster than the terrestrial one probably as a survival adaptive strategy. Intra-speciic coparison The coparison o growth paraeters in the Barbary partridge originated ro low- and high elevations, revealed signiicant dierences in the values o the asyptotic body weight with birds ro ountains being larger and heavier. These results are in concordance with data on ean adult body weights reported or Barbary partridges ro two other Moroccan localities, one located in the High Atlas ountains and the other one in the plain (North Morocco) (64 g vs. 56 g in adult cocks and 497 g vs. 455 g in adult hens) (Alaoui 21). So, this dierence in adult body size observed in Barbary partridges between elevations in the ield are subsequently aintained in the aviary. This would iply that there were persistent genetic dierences between the two studied populations or that the aternal eects (i.e., internal egg quality) inluence the inal body size according to elevation. Moreover, and according to Bergan s rule, larger body size in cooler ountainous areas would be an advantage or theroregulation as heat loss is ore rapid or sall than or large endothers because o the high surace area to volue ratios in the orer (Liknes & Swanson 1996). Nevertheless, birds show no relationship between the strength o Bergann s rule and body size (Ashton 22). This author suggests that the asting endurance is probably a ore iportant actor than the traditional hypothesis o heat conservation. Fasting endurance hypothesis proposes that larger size is avoured in ore seasonal environents because larger anials can store ore at and can use those at stores or greater survival during seasonal stress (Boyce 1979, Lindstet & Boyce 1985). The scaling o at stores and etabolis with body size coners an absolutely (but not rela- 5

7 Barbary partridge growth patterns tively) longer survival tie, e.g. greater asting endurance during seasonal resources shortages or larger anials. As growth, data are diicult to obtain on ree-living growing Barbary partridges, the lack o dierences in all other orphological traits and growth paraeters (including size at hatching) between low- and high elevations in the coon captive environent could be explained according two possible scenari. The irst one supposes that this lack o dierences between growth paraetrs exist in the wild and is aintained when populations are raised in coon environent. This would iply that the populations are genetically the sae, and that their orphological traits are not aected by phenotypic plasticity in response to conditions that dier between elevations in the ield. The second scenario assues that dierences exist between elevations in the ield, but traits values converge in the coon environent. This would iply that dierences in the ield are due to phenotypic lexibility in response to dierences in environental conditions between low- and high elevation habitats. According to the irst scenario, siilar growth paraeters in the ield aintained in captivity would ean that growth rates are physiologically axiized as suggested in soe passerine birds (Rickles 1973, King & Hubbard 1981). In the second scenario, potential dierences in growth paraeters between elevations in the wild, would assue that growth rates are rather subaxial and optiized in relation to the local environent. Acknowledgents This study was carried out under the auspices o Direction Régionale des Eaux et Forêts du Haut Atlas de Marrakech, and the Natural History Museu o Marrakech, Cadi Ayyad University, Marrakech, Morocco. REFERENCES Akil M. & Boudedja S., 21. Reproduction de la Perdrix gabra Alectoris barbara dans la région de Yakourn (Algérie). Gae Wildlie Science 18: Alaoui M., 21. Mise en évidence d une race de ontagne de Perdrix gabra Alectoris barbara dans le Haut-Atlas arocain. Gae Wildlie Science 18: Alaoui M., Ecologie de la ponte chez la Perdrix gabra Alectoris Barbara au Maroc. Gibier et Faune Sauvage 9: Ashton K.G., 22. Patterns o within-species body size variation o birds: strong evidence or Bergann s rule. Global Ecology and Biogeography 11: Barbato G.F., Genetic architecture o growth curve paraeters in chickens. Theoretical & Applied Genetics 83: Bears H. Drever M.C. & Martin K., 28. Coparative orphology o dark-eyed juncos Junco hyealis breeding at two elevations: a coon aviary experient. Journal o Avian Biology 39: BirdLie International., 24. Birds in Europe: Population Estiates, trends and Conservation status. BirdLie International, Cabridge. Boyce M.S., Seasonality and patterns o natural selection or lie histories. Aerican Naturalist 114: Crap S. & Sions K.E.L., 198. Handbook o the birds o Europe, the Middle East and North Arica, II. Oxord University Press, Oxord. Dietz M.W. & Rickles R.E., Growth rate and aturation o skeletal uscles over a size range o Gallior Birds. Physiological Zoology 7: Foronda P., Casanova J., Figueruelo E., Abreu N. & Feliu C., 25. The helinth auna o the Barbary partridge Alectoris barbara in Tenerie, Canary Islands. Journal o Helinthology 79: Hollander P.L., Horonal aspects o salt and water balance in Alectoris barbara. Yale University, Ph.D., US., 169 p. King J.R. & Hubbard J.D., Coparative patterns o nestling growth in white-crowned sparrows. Condor 83: Liknes E.T. & Swanson D.L., Seasonal variation in cold tolerance, basal etabolic rate, and axial capacity or therogenesis in white-breasted nuthatches Sitta carolinensis and downy woodpeckers Picoides pubescens, two unrelated arboreal teperate residents. Journal Avian Biology 27: Madge S. & Mcgowan P., 22. Pheasants, Partridges e Grouse. Including Buttonquails, Sandgrouse and Allies. Christopher Hel, London. O Connor R.J., The growth and developent o birds. John Wiley and sons, London. Ogilvie D.M., 197. Teperature selection in day-old chicken Gallus doesticus, and young Japanese quail Couturnix couturnix japonica. Canadian Journal Zoology 48: Pis T., 212. Growth and developent o chicks o two species o partridge: the Grey partridge Perdix perdix and the chukar Alectoris chukar. British Poultry Science 53: Rickles R.E., Patterns o growth in birds II. Growth rate and ode o developent. Ibis 115: Rickles R.E., Patterns o growth in birds. V. A coparative study o developent in the starling, coon tern and Japanese quail. Auk 96: 1-3. Stark J.M. & Rickles R.E., Avian growth and developent. Oxord University Press, Oxord. Strack J.M. & Sutter E., 2. Patterns o growth and heterochrony in Moundbuilders (Megapodidae) and owl (Phasianidae). Journal o Avian Biology 31: Associate Editor: Bruno Massa 51