Growth of Jackass penguin chicks (Spheniscus demersus) hand reared on different diets

Jackass penguin chicks from the age of about 10 days were hand reared on different diets: mullet Liza richardsoni , anchovy Engraulis capensis and squid Loligo reynaudi , until they fledged. The weight of food fed and the daily weight increment of the chicks was measured. Excreta were collected every 5–6 days and analysed to establish metabolized energy and metabolic efficiency. Culmen measurements were taken regularly and plotted against age. The age, weight and sum of food fed up to fledging was compared between diets as well as with field data. Compensatory growth was exhibited when stunted chicks on a relatively poor diet had their diet changed to a relatively better diet.     

Water loss from Jackass Penguin Spheniscus demersus eggs during natural incubation

The water budget of incubating Jackass Penguin eggs was studied on Marcus Island, South Africa, and complementary measurements were made in the laboratory. The mean ambient temperature was 16-5 "C and the mean humidity was 12-4 Torr (89% relative humidity). The temperature of incubated live and water-filled eggs ranged between 14^oCand 37 ^oC. The mean calculated egg temperature was 34-9' C. The mean brood patch temperature was 37-1 ^oC, slightly lower than the cloacal temperature (37.8 ^oC). The mean brood patch area was about 38 cm². The rate of water loss was 411 mg day^-1. The total diffusive water loss during 37 days of incubation was, as predicted, 15-2% of the initial 100-3 g egg mass. The total pore number was 6245 per egg and the shell thickness was 577 fira. It is suggested that the eggshell parameters, incubation length and nesting behaviour are compensated in such a way that an egg-to-nest water vapour pressure difference lower than commonly found is sufficient to bring about the normal total water loss.     

Plasma arginine vasotocin and angiotensin II in the water deprived Kelp gull (Larus dominicanus), Cape gannet (Sula capensis) and Jackass penguin (Spheniscus demersus)

1. The basal levels of the osmoregulatory hormones, arginine vasotocin (AVT) and angiotensin II (AII) were measured (by radioimmunoassay) in the plasma of conscious Kelp gulls, Cape gannets and Jackass penguins. 2. The responses of the hormones to similar degrees of hypertonicity and hypovolemia caused by water deprivation have also been determined. 3. Dehydration elevated plasma AVT and plasma AII in all three species. 4. The AVT concentration was increased by 2-4 fold and although in each case the correlation between plasma osmolality and plasma AVT was highly significant (2P less than 0.01), the sensitivity of release was greater in the gull (1.13 pg/ml per mOsm/kg) than in the gannet (0.36 pg/ml per mOsm/kg) or penguin (0.44 pg/ml per mOsm/kg). 5. Dehydration increased plasma AII 3-fold in the three bird types.     

Herpesvirus-like infection in black-footed penguins (Spheniscus demersus)

A herpesvirus-like infection is described in the black-footed penguin (Spheniscus demersus). Clinically, the infection was characterized by debilitation and respiratory distress. Histopathological lesions were confined to the respiratory tract and consisted of inflammation and syncytial cell formation with Type A intranuclear inclusions in sinuses, trachea, and mainstem bronchi. Electron microscopy demonstrated polyhedral viral particles 80-140 nm in size consistent with Herpetoviridae. The lesions resembled those seen in infectious laryngotracheitis.     

Group Size in Foraging African Penguins (Spheniscus demersus)

Diving synchrony was examined for varying group sizes of African penguins (Spheniscus demersus) travelling to their foraging grounds from their breeding islands. Groups of fewer than 12 birds always dived synchronously, whereas groups of more than 17 birds always dived asynchronously. Since travelling penguins do not dive deeply, large groups of birds can remain together irrespective of diving synchronization. Observations from boats showed that foraging penguins rarely occurred in groups of more than 17 birds. We suggest that groups of penguins that do not have synchronized dives cannot forage effectively, because foraging penguins dive deeply.     

Visual pigments and oil droplets in the penguin,Spheniscus humboldti

Summary The photoreceptors of the penguin,Spheniscus humboldti, were examined using a microspectrophotometer. The cones could be divided into three classes based on their visual pigment absorbance spectra [max 403, 450 and 543 nm (Fig. 1)], and into five classes based on their visual pigment-oil droplet combination (Fig. 4). Oil droplets were of three types (Fig. 2). The rods contained a rhodopsin with max at 504 nm. No double cones were observed. The penguin should be capable of good wavelength discrimination in the blue-green region of the spectrum but with poor discrimination at longer wavelengths. It is concluded that the spectral properties of the cone types indicate that the photopic vision ofS. humboldti is adapted to the spectral qualities of its aquatic environment.     

上海动物园圈养斑嘴环企鹅种群统计学与遗传学分析

根据1984—2017年上海动物园圈养斑嘴环企鹅Spheniscus demersus数据,应用Sparks 1.6和PMx 1.0进行数据整理、统计学和遗传学分析。结果显示,该种群数量呈增长状态,但也存在如下问题:(1)种群中未知性别比例过高,占46.25%;(2)种群年龄结构不合理,0~4岁及7~8岁个体数量不足,育龄个体中未知性别的数量较多;(3)雌雄个体0~1岁、10~13岁的死亡率偏高,曲霉菌病是致死的主要原因;(4)参与繁殖的奠基者数量(9只)和潜在奠基者数量(1只)少,分属2个家系,且后代数和贡献值明显不均衡,种群的平均亲缘关系值为0.097 2,种群的平均近亲繁殖系数为0.099 5,存在近亲繁殖现象;(5)虽然现有种群保留了野生个体90.28%的基因多样性,但未来丢失也较快。因此,为了建立健康的斑嘴环企鹅种群,应尽快引进新的血统,开展性别鉴定工作,采取预防为主、防治结合的方式降低曲霉菌病的致病率;采用各种技术如人工授精技术提高企鹅受精率,为繁殖个体,尤其是后代数量过少的奠基者个体提供均等的繁殖机会,从而加强上海动物园圈养斑嘴环企鹅的种群管理。     

Vision of the Humboldt penguin (Spheniscus humboldti) in air and water

Refractive states measured by retinoscopy and photorefraction indicate that the eyes of the Humboldt penguin, Spheniscus humboldti, are approximately emmetropic in air and water. Extensive myopia in air, as predicted by earlier authors and by a recent anatomical study, is non-existent. Photorefractive measurements of the refractive state, in water, of the Humboldt penguin indicate that it can accommodate sufficiently to make up the loss of the refractive power of the cornea. The cornea of the Humboldt penguin is flattened relative to the overall size of the eye. In all these respects (corneal flattening, and accommodation in air and water) the eyes of Humboldt penguins are like those of gentoo, (Pygoscelis papua), rockhopper (Eudyptes crestatus), Magellanic (Spheniscus magellanicus), and king penguins (Aptenodytes patagonica).     

Characterization of microsatellite loci in Humboldt penguin (Spheniscus humboldti) and cross‐amplification in other penguin species

The Humboldt penguin (Spheniscus humboldti) was once very common throughout its range along the coast of Peru and Chile. Today, listed as endangered, it is crucial to gain an understanding of gene flow and levels of genetic variation between breeding colonies to protect this species effectively. We developed seven microsatellite primers to investigate gene flow and population structure among four colonies. Locus‐specific allelic diversity ranges from five to 11 alleles and observed heterozygosity ranges from 0.50 to 0.88. These markers cross‐amplify in eight penguin species over five genera.     

Of squeezers and skippers: factors determining the age at moult of immature African Penguins Spheniscus demersus in Namibia

We used banding and resighting records of 391 African Penguins Spheniscus demersus banded as chicks and later resighted during immature moult to explain the roles of date of fledging and age at moult in determining the season of moult and its timing within the season. Breeding was continuous, but immature moult occurred mainly during spring and summer. Age at immature moult extended over 11 months, from 12 to 23 months after hatching. Birds that fledged during summer and early autumn generally moulted during the next moult season (squeezers), whereas birds that fledged in late autumn, winter and spring skipped the next moult season to moult only the following season (skippers). There was a significant relationship between age at moult and moult date, with young birds moulting later in the season than older birds. The age at moult of immature birds appears to be constrained by minimum age, moult seasonality and plumage wear. Birds that fledged over nearly 2 years moult during one season. Counts of moulting immature African Penguins have not been used to estimate year-class strength and post-fledging survival owing to the wide range of ages at immature moult. Our results provide the means of assigning recruits to specific age groups.     

The first record of Dirofilaria immitis infection in a Humboldt penguin, Spheniscus humboldti

Dirofilaria immitis infection is an important parastic disease in many mammals, especially canids, but has not been reported in bird hosts. Filarial worms were isolated from the lumen of the right atrium of the heart and the connective tissue of the lung of a captive female Humboldt penguin, Spheniscus humboldti, that died at a zoo in Japan. One of these worms was observed morphologically and identified as D. immitis by features such as 4 pairs of cephalic papillae, 1 pair of cervical papillae, esophagus divided into 2 regions, 4 pairs of pre-anal papillae, 5 pairs of post-anal papillae, and unequal spicules. In addition, the partial DNA sequence (234 bp) of mitochondrial CO / gene of the filarial worm was identical to that of D. immitis. This is the first report of D. immitis infection in a bird.     

Fibre types in primary ‘flight’ muscles of the African Penguin (Spheniscus demersus)

The African penguin (Spheniscus demersus) is an endangered seabird that resides on the temperate southern coast of Africa. Like all penguins it is flightless, instead using its specialized wings for underwater locomotion termed ‘aquatic flight’. While musculature and locomotion of the large Antarctic penguins have been well studied, smaller penguins show different biochemical and behavioural adaptations to their habitats. We used histochemical and immunohistochemical methods to characterize fibre type composition of the African penguin primary flight muscles, the pectoralis and supracoracoideus. We hypothesized the pectoralis would contain predominantly fast oxidative–glycolytic (FOG) fibres, with mainly aerobic subtypes. As the supracoracoideus and pectoralis both power thrust, we further hypothesized these muscles would have a similar fibre type complement. Our results supported these hypotheses, also showing an unexpected slow fibre population in the deep parts of pectoralis and supracoracoideus. The latissimus dorsi was also examined as it may contribute to thrust generation during aquatic flight, and in other avian species typically contains definitive fibre types. Unique among birds studied to date, the African penguin anterior latissimus dorsi was found to consist mainly of fast fibres. This study shows the African penguin has specialized flight musculature distinct from other birds, including large Antarctic penguins.     

Pond Use by Captive African Penguins (Spheniscus demersus) in an Immersive Exhibit Adjacent to Human Bathers

Nonhuman animals in zoos are exposed to a continuous human presence, which affects their behaviors and welfare. However, little is known about what role the “visitor effect” has on penguins in captivity. The African penguin (Spheniscus demersus) is an endangered species commonly housed in zoos worldwide. The aim of this study was to evaluate whether the abundance of human bathers could reduce the average time spent in the water of a colony of African penguins housed in an exhibit where their pond habitat was adjacent to a swimming pool. Observations were carried out on 7 penguins in the summer of 2009. Data were collected during 3 time periods (Time 1 [T1] = opening of the swimming season, Time 2 [T2] = core of the season, Time 3 [T3] = late season) of 14 days each. The human disturbance caused by bathers strongly reduced the pond use by penguins at T1 and T2, especially when there were large numbers of visitors. However, at T3, we observed that the overall use of the pond by penguins increased, and the average duration of their diving was no longer dependent on the number of visitors.     

The eye of the humboldt penguin, Spheniscus humboldti: visual fields and schematic optics

Construction of a schematic eye indicates that the eye of Spheniscus humboldti is aquatic in design. The lens has a power of 100 dioptres (D) while (in air) the cornea has a power of 29 D. In air, the eye is myopic (approximately 28 D) but in water it is emmetropic. Minimum pupil size would seem insufficient to allow the pupil to function as a stenopaic aperture and increase depth of focus sufficiently to overcome the eye's aerial myopia. Entry into water reduces maximum image brightness by approximately three times. In air, the maximum width of the retinal binocular field is 45 degrees and this occurs approximately 10 degrees above the line of the bill. The bill intrudes into the retinal field and binocular field width in the plane containing the bill and the optic axes is 28 degrees. The vertical extent of the binocular field is 125 degrees. In the plane containing the optic axes the cyclopean field equals 282 degrees and the optic axes diverge by 116 degrees. In this plane the mean uniocular field is 155 degrees with the temporal hemifield approximately 11 degrees larger than the nasal hemifield. Entry into water reduces the widths of the visual fields such that maximum binocular field width is only 17 degrees and the vertical extent is reduced to about 80 degrees. Binocular vision is lost in the plane of the bill, and the uniocular retinal field is reduced by 32 degrees and the cyclopean field by 36 degrees.     

Evidence for gene flow differs from observed dispersal patterns in the Humboldt penguin, Spheniscus humboldti

The Humboldt penguin, once common throughout its range, is today listed as Vulnerable by the IUCN. Mark-recapture and telemetry studies indicate that adult Humboldt penguins are sedentary, suggesting strong genetic differentiation between colonies. We developed genotypes for 336 individuals at 12 microsatellite loci sampled at four different localities spanning the entire range of this species. Results show that long-term gene flow has occurred but appears to be affected by geographic distance as pairwise F _ST comparisons involving the colony at Punta San Juan (Peru) and the two colonies at Algarrobo (central Chile) and Puñihuil (southern Chile) are significant. Bayesian estimates of recent migration rates indicate substantial dispersal among all colonies. Despite the dramatic decline in numbers, we did not observe a bottleneck in any population. Furthermore, we did not detect a founder effect in the recently discovered colony at Puñihuil. As our indirect estimates signal strong gene flow between populations, we suggest that Humboldt penguin colonies need to be managed as a metapopulation rather than as discrete management units.     

Semen collection,characterization, and cryopreservation in a Magellanic penguin (Spheniscus magellanicus)

A cooperative method was developed for collecting semen from a Magellanic penguin. Ejaculate parameters and semen production during a breeding season were characterized. Experiments were performed to study the effect on penguin spermatozoa of two temperatures (4°C and 21°C) for short‐term storage, and two cryoprotectants (dimethylsulfoxide [DMSO] and ethylene glycol [EG]) for long‐term storage (cryopreservation). All dilutions were made using modified Beltsville Poultry Semen Extender. Sperm quality was assessed by evaluating motility and forward progression (sperm motility index [SMI]), viability, and morphology. A total of 39 ejaculates was collected over the 40‐day study period. Thirty‐eight ejaculates contained spermatozoa, but semen quality decreased toward the end of the study period. Varying levels of urate contamination were present in all ejaculates. Sperm quality parameters were similar for diluted samples held at 4°C and 21°C, and samples maintained high numbers of viable (77.8 ± 5.4%) and morphologically normal (67.9 ± 2.5%) spermatozoa at 3 hr. SMI and percentage of viable sperm decreased (P < 0.05) and the number of spermatozoa with a bent head or midpiece increased (P < 0.05) for both temperature groups over the 3‐hr storage interval. DMSO and EG were equally effective in maintaining penguin sperm quality parameters during the cryopreservation and thawing process. Frozen‐thawed semen maintained 69 ± 5 and 78 ± 3% of its pre‐freeze SMI and viability, respectively. SMI and viability decreased slightly during the cooling and equilibration phases but remained relatively stable during the 3‐hr storage interval post‐thaw. Frozen‐thawed semen also exhibited an increase (P < 0.05) in spermatozoa with a bent head or midpiece over time. The pre‐freeze SMI was higher (P < 0.05) for ejaculates with low levels of urates (clean ejaculates) compared with ejaculates with high levels of urate contamination, but sperm viability and morphology were similar (P > 0.05). Both SMI and viability of frozen‐thawed spermatozoa were higher (P < 0.05) for clean than for contaminated ejaculates. This is the first report on penguin ejaculate parameters, semen production, and preliminary methods for short‐ and long‐term semen storage. Zoo Biol 18:199–214, 1999. © 1999 Wiley‐Liss, Inc.