Hatching Season Research Articles

Productive and Reproductive Performances and Status of Chicken Breeds in Two Districts of South-Omo Zone, Ethiopia

The study targeted the productive and reproductive performance and status of breeds was conducted in two districts of the South-Omo zone, Ethiopia. A purposive sampling method was used to select districts, kebeles, and households and then, stratified to local, exotic, and mixed-breed rearing households. The composition of pullets (3.603), chicks (3.5), and layers (3.39) were highest than that of Cockerels (2.107) and Cocks (1.79). The more eggs/clutch/hen (26.2), the highest matured body weight (3.26 Kg), and the fast age of sexual maturity (5.4 months) were recorded for exotic breeds than the hybrid and local. The hatchability difference was due to the difference in broody hen, egg source, egg duration, egg size, and the season of hatching. The traits such as mothering ability, disease resistance, and production with conditional supplementation of the local breed were diluted. The productive and reproductive performance of the local ecotypes was low and the improved breeds not expressed their full genetic potential. The population of local breeds was diluted and decreased, antagonistically, that of the exotic breeds is increasing, and if it is not terminated near future we will lose distinctive traits of local breeds. Hence, regular supplementation of feed and conservation of exploiting genes were recommended to exploit the full genetic potential of breeds and sustain the diluting genes of local breeds, respectively.

Effect of Non-genetic Factors on Growth and Production Traits in Two Strains of Japanese Quails

Background: The growth of birds is a function of both genetics and environment involving change leading into improvement in weight, shape, size, volume, etc. Study of important non-genetic factors is important in view of formulating future selection and breeding strategies in different poultry species. Methods: The present study was done on 1246 numbers of Japanese Quails (Coturnix coturnix japonica) of two strains i.e., black and white distributed in three generations during 2020-21. The fixed effects of gender, season of hatch, strain and generations on various fortnightly body weights (FNBW), average daily weight gain (ADWG), relative growth rate (RGR) and some production traits were studied. Result: Significant (p≤0.01) differences in black and white strain as well as male and female quails for hatch weights were observed. The maximum ADG was during 4th to 6th wk whereas the RGR was highest during first fortnight (hatch-2nd wk). Significantly (p≤0.01) higher average egg weights (AEW) were observed in white quails. Part egg production (PEP) and AEWs were higher during summer and winter hatches, respectively. The present investigation elucidates the significance of different non-genetic factors on important growth and production performances for further selection in quails.

Saving hawksbill sea turtles from rats, cats and Hurricane Ida

Hatching season on the Caribbean island of Barbados is a busy time for Carla Daniel. Hatching season on the Caribbean island of Barbados is a busy time for Carla Daniel.

Saltwater crocodile and human conflict around Bhitarkanika National Park, India: A raising concern for determining conservation limits

Recently, there has been an increase in saltwater crocodile-human interaction around Bhitarkanika National Park and the present article briefs the recent attacks of saltwater crocodiles on humans in the region. Information regarding the attacks was extracted from national newspapers and CrocBITE. It is found that in last 15 years, total of 57 persons got attacked by saltwater crocodile (Crocodylus porosus Schneider, 1801) in and around Bhitarkanika National Park. The trend of incidents shows that the attack on humans is increasing every year, which might be due to the increase in the density of C. porosus in a limited area of natural habitat. July to October was considered as the critical season when maximum attacks occur as this is the nesting and probable hatching season of C. porosus during which the species remain highly aggressive. In the last 42 years, since the crocodile breeding and management project implemented in India, the conservation of the species has resulted in a significant increase of their number in Bhitarkanika National Park. Existing reports suggest that the present density of C. porosus in Bhitarkanika National Park has surpassed the value (Five to six crocodiles per km length of water) which was proposed while initiating the conservation programme. The present scenario demands for development and implementation of an updated management plan for the coexistence of humans and saltwater crocodiles. The conservation and management strategy of SWCs shall include determination of carrying capacity of the sanctuary, minimizing exploitation of natural resources, relocation of the SWCs to other feasible sites, creating awareness among local people, development of alternative livelihood for the locals and construction of more number of bath huts along the water bodies.

Effects of Strain and Non-genetic Factors on the Egg Qualities and Carcass Characteristics of Indigenous Guinea Fowl (<i>Numida meleagris</i>)

The objective of this study was to investigate the effects of strain and non-genetic factors on egg qualities and carcass characteristics of indigenous Guinea fowl. The study was carried out at the Poultry Section of the Department of Animal Science Education, University of Education, Winneba, Mampong-Ashanti, Ghana, from 2014 to 2016. Four strains of local Guinea fowls; namely Pearl, Lavender, White and Black were used. Three non-genetic factors were considered; season of hatch, generation and sex of bird. Data were collected on 603 local Guinea fowls for the study. Data were analysed using the General Linear Procedure (GLM) of SAS. Results obtained showed that egg weight was significantly (p<0.05) affected by generation. Parental generation had higher value (37.9±3.98) than the first filial generation (37.64±0.93); however, strain and season had no significant (p>0.05) effect on egg weight and hatch weight. Generation had significant (p<0.05) effect on yolk weight. Parental and first filial generations had 13.7±0.24 and 13.2±0.21 yolk weights respectively. Haugh unit was significantly influenced by strain; white had highest (79.04±2.49) Haugh unit, followed by lavender (77.67±2.03), black (76.51±2.49) and pearl (71.14±1.2). Generation had significant (p<0.05) influence on live and dressing weights. Sex had no significant (p>0.05) effect on head, neck and shank weights. The interaction of sex and Strain had significant (p<0.05) influence on live, heart and intestine weights. Generation had no significant (p<0.05) effect on carcass characteristics. Strain had significantly (p<0.05) influence on moisture and carbohydrate. In conclusion, the strains and non-genetics factors (sex, season and generation) influence the egg and carcass qualities of indigenous Guinea fowl, hence the effects of these factors must be considered in genetic selection of indigenous Guinea fowls.

Daily growth patterns and age-at-recruitment of the anchoveta Engraulis ringens as indicated by a multi-annual analysis of otolith microstructure across developmental stages.

The anchoveta (Engraulis ringens) plays a key role in the ecology of the Humboldt Current System and is of major economic importance; however, many aspects of its early life history are still poorly understood. In this study, an analysis of daily age and length patterns was carried out using the sagittal otoliths from wild larvae (0-0.2 cm standard length, LS ), pre-recruits (3-6 cm total length, LT ), recruits (7-12 cm LT ) and young adults (12-15 cm LT ). Additionally, variability in growth and age at recruitment (AR ) were evaluated for recruits caught in northern Chile in 1973, 1982, 2009, 2010, 2012, 2013, 2014 and 2015. The age-length relationship showed four allometric patterns that were well described by Laird-Gompertz models. The absolute growth rates at the inflexion point (GAR ) were 0.56, 0.75, 1.22 and 1.16 mm d-1 for larvae, pre-recruits, recruits and young adults, respectively. At the interannual scale, GAR values were always >1 mm d-1 (mean ± S.D. 1.37 ± 0.21 mm d-1 ; range 1.12-1.64 mm d-1 ), irrespective of the season of hatching (i.e. winter v. spring); additionally, in most cases, GAR values were reached before the second month of life (mean ± S.D. 50.47 ± 9.73 days) at c. 4 cm LT (mean ± S.D. 4.22 ± 0.29 cm). Mean AR was < 150 days (112 ± 29 days; range 75-149 days); in contrast, estimates of AR were higher and growth rates were lower in 1973, 1983 and 2000. These results demonstrate very fast growth and early AR of anchoveta in northern Chile, suggesting most fish are removed by the fisheries at very early ages. An evaluation of the implications of these results on stock assessment and management of this species is highly recommended.

キウイフルーツに対するキクビスカシバ（チョウ目：スカシバガ科）の産卵・加害部位と成虫の発生消長および薬剤防除法

Lepidopteran larvae damage to the branches of cultivated kiwifruit is a serious problem in the southwest part of Ehime Prefecture, Japan. We reared these larvae using seedlings of kiwifruit, and found that this species was a clearwing moth, Nokona feralis（Leech）. After emergence, the 1st instar larvae bored into the current shoots from the base of the petiole, and almost all of the leaves near the positions where the larvae bored were withered. Larvae moved to 30–40 mm diameter branches and bored into them, and expelled a large amount of frass from the site the larvae attacked. The puparia were observed mainly on 20–50 mm diameter branches. One to five eggs were laid, mainly on the petiole base. Ovipositions by females were observed until the middle of October. Eggs overwintered and then larvae hatched the next April. The hatching rate was 30.4% and 39.2% of eggs were attacked by a parasitoid wasp. Males were captured by pheromone traps from early September to the middle of October, and a peak of male capture was observed from late September to early October. Of 28 pheromone traps placed across Ehime Prefecture, only 4 traps in the southwest region（Ainan Town, Uwajima City, and Yawatahama City）captured males. To suppress larval attack, some insecticides were carried out in the season of larval hatch. Cypermethrin, methidathion（DMTP）, and cartap effectively prevented the larval attack to kiwifruit.

Hawksbill × loggerhead sea turtle hybrids at Bahia, Brazil: where do their offspring go?

Hybridization between hawksbill (Eretmochelys imbricata) and loggerhead (Caretta caretta) breeding groups is unusually common in Bahia state, Brazil. Such hybridization is possible because hawksbill and loggerhead nesting activities overlap temporally and spatially along the coast of this state. Nevertheless, the destinations of their offspring are not yet known. This study is the first to identify immature hawksbill × loggerhead hybrids (n = 4) from this rookery by analyzing the mitochondrial DNA (mtDNA) of 157 immature turtles morphologically identified as hawksbills. We also compare for the first time modeled dispersal patterns of hawksbill, loggerhead, and hybrid offspring considering hatching season and oceanic phase duration of turtles. Particle movements varied according to season, with a higher proportion of particles dispersing southwards throughout loggerhead and hybrid hatching seasons, and northwards during hawksbill season. Hybrids from Bahia were not present in important hawksbill feeding grounds of Brazil, being detected only at areas more common for loggerheads. The genetic and oceanographic findings of this work indicate that these immature hybrids, which are morphologically similar to hawksbills, could be adopting behavioral traits typical of loggerheads, such as feeding in temperate waters of the western South Atlantic. Understanding the distribution, ecology, and migrations of these hybrids is essential for the development of adequate conservation and management plans.

Season-dependent Postembryonic Maturation of the Diurnal Rhythm of Melatonin Biosynthesis in the Chicken Pineal Gland

Previously, we have demonstrated that the timing of the nocturnal peak of activity of the pineal arylalkylamine-N-acetyltransferase – a key enzyme in the melatonin biosynthesis pathway – in 3-wk-old chickens kept from the day of hatch under controlled laboratory conditions (L:D 12:12) varies depending on the season of hatch (summer vs. winter). The present study was undertaken to answer the following questions: (1) are season-related differences seen in the level of transcription of genes encoding enzymes of the melatonin biosynthesis pathway? (2) Does the pineal content of the main precursor (serotonin) and the final product (melatonin) exhibit age- and season-related changes? (3) At which step in postembryonic development are these season-related variations in pineal gland function most pronounced? Male Hy-line chickens hatched in the summer or winter, from eggs laid by hens held on L:D 16:8, were kept from the day of hatch under L:D 12:12 conditions. At the age of 2, 9, or 16 d, chickens were sacrificed every 2 h over a 24-h period and their pineal glands, isolated under dim red light, were processed for the measurement of (i) the level of Aanat and Asmt (acetylserotonin O-methyltransferase) mRNAs encoding the two last enzymes involved in melatonin biosynthesis, (ii) the activity of these enzymes, and (iii) the pineal content of serotonin and melatonin. Circadian rhythmicity of all the measured parameters was evaluated by the cosinor method. The levels of Aanat mRNA, AANAT enzymatic activity, and the pineal melatonin content changed during postembryonic development in a manner that was dependent on the season of hatch. Furthermore, the diurnal profile of Asmt mRNA was elevated during the light phase. In “winter” birds, the pattern and amplitude of the diurnal rhythm of accumulation of this transcript did not change with age, while in “summer” birds it increased in an age-related way. In contrast, the enzymatic activity of hydroxyindole-O-methyltransferase (HIOMT; encoded by the Asmt gene) did not change rhythmically, although it increased with age in a season-related way. In “winter” chickens, the pineal serotonin content was low, regardless of age, and did not change rhythmically, whereas in “summer” individuals the serotonin rhythm was already well established by day 2, with the amplitude increasing with age. These results confirm the existence of a “seasonal memory” operating within the chicken pineal gland, although the mechanism(s) underlying this phenomenon have yet to be characterized.

Season-Related Differences in the Biosynthetic Activity of the Neonatal Chicken Pineal Gland

Influence of the season of hatch on the functional characteristics of the pineal gland was examined in neonatal Hi-Line male chickens. The pineal glands from 2-day-old birds hatched in and winter, and kept from the day of hatch in artificial lighting conditions (12L:12D), were isolated under dim red light in the middle of the day or night. The pineal glands were analyzed to characterize their melatonin biosynthetic activity: (1) expression of the Arylalkylamine- N-acetyltransferase and Hydroxyindole-O-methyltransferase genes, encoding the final two enzymes of the melatonin biosynthesis pathway; (2) the activity of AA-NAT and HIOMT; and (3) the content of the main substrates of this pathway, tryptophan (TRY) and serotonin (5-HT). Daily changes in pineal AA-NAT activity were observed in chickens hatched in both seasons, with a more pronounced nocturnal increase in summer. In contrast, the level of Aa-nat gene expression, although exhibited the same nocturnal/diurnal pattern in both seasons, was much lower in the summer. The activity of HIOMT was season- and daytime-independent. In winter chickens the pineal content of 5-HT was low and stable, while in summer birds it was correlated with levels of AA-NAT activity and Aa-nat gene expression. TRY content was very high and exhibited neither daily nor seasonal changes. The pineal gland of newly hatched chickens kept in controlled 12L:12D conditions exhibits daily variations in melatonin biosynthetic activity influenced by the season. This suggests a maternal effect on the perinatal/postnatal development of the circadian clock residing in the chicken pineal gland.

Direct responses in breeding values to selection of ostriches for liveweight and reproduction

Estimates of genetic parameters and genetic trends for reproductive traits and for liveweight at the commencement of breeding were obtained using data from a pair-mated ostrich flock located at Oudtshoorn in South Africa. Heritability estimates were 0.17–0.18 for egg production, 0.15–0.17 for chick production and 0.35–0.37 for liveweight. Female permanent environmental effects amounted to 0.11–0.17 for egg production, 0.14–0.19 for chick production and 0.30–0.31 for liveweight. Service sire exerted significant effects only on egg production (0.03–0.08) and chick production (0.05–0.10). Genetic correlations of reproductive traits with liveweight were not different from zero. Initial selection in the flock was based on reproduction, in the sense that replacements were descended from the females with the highest uncorrected number of chicks produced during their season of hatch (Chick Production line). Animals that were hatched during the period from 1996 to 2006 were used to establish two more populations. The heaviest birds at ~16 months of age were used as replacements in the line selected for liveweight (Liveweight line). Birds selected for the Control line were of average uncorrected liveweight at ~16 months, and were descended from females that produced an average number of chicks in their season of hatch. Overall, the Liveweight line had higher breeding values than the Control line for the period from 1996 to 2006. The response seemed to be associated with screening from the larger population on breeding values for liveweight, as no cumulative genetic gains were evident since 1996. Breeding values for chick production in the Chick Production line were increased by 3.1% per year from 1990 to 2006. Regressions of individual breeding values in the Control line on the year of hatch indicated no genetic change in either liveweight or chick production. Genetic change in particularly reproduction thus seems feasible in commercial ostriches.

Palatability of autotrophic dinoflagellates to newly hatched larval crabs

To determine the general palatability of autotrophic dinoflagellates to newly hatched crab larvae and whether there are taxonomic, predator/prey size relationships, or toxicity components to their ability to discriminate among dinoflagellates, larvae of six species of crabs from two families were fed 16 species/strains of dinoflagellates from three orders. Dinoflagellate cell length ranged from 18 to 50 µm, and toxic and non-toxic species/strains were included. Experiments measuring incidence of prey ingestion, grazing rates on individual constituents of selected prey combinations, and development on one toxic species shown to be readily ingested were conducted between 2000 and 2002. Thirteen of sixteen dinoflagellates were palatable to larvae, with no consistent pattern of prey discrimination based on taxonomic affinity, toxicity, larval hatching season, or predator/prey size relationships. Although the three dinoflagellates not ingested were toxic, three other toxic species/strains were ingested, with accelerated mortality occurring in the one case. Ingestion of non-favored prey occurred only at very low rates when mixed with readily ingested prey, indicating selectivity. Larvae hatching in winter generally ingested dinoflagellates as readily as did zoeae hatched in spring and summer. Newly hatched larvae ingested a wide variety of dinoflagellates, while discriminating among related species. Such discrimination will not always prevent larval ingestion of prey that will result in mortality.

The in situ relationships between season of hatching, growth and condition in the southern calamary, Sepioteuthis australis

This paper examines seasonal patterns in growth and condition of Sepioteuthis australis from temperate waters of Tasmania, Australia. Growth was described by a power function and was fast for a temperate species, with an average rate over the lifetime of 4–5% BW day–1. Sepioteuthis australis is an annual species, however spawning and hatching of juveniles appears to occur all year round. Analysis of individual juvenile growth demonstrated a correlation between seasonally increasing temperatures and progressively faster growth. Season of hatching also had a clear effect on adult growth; summer-hatched individuals were larger at 170–190 days of age compared with winter-hatched individuals (1002 ± 98 g and 632 ± 27 g respectively). The length–mantle weight relationship of adults was also dependent on season of hatching, with individuals hatched in summer and spring having heavier mantles at a given length than those hatched in winter or autumn. Differential rates of growth or varying levels of condition, or perhaps both, may affect the survivorship of individuals. Growth, condition and potentially lifespan of S. australis are dependent on environmental factors, with the dynamic nature of oceanographical conditions on the east coast of Tasmania resulting in a highly variable and fluctuating population structure.

Larval and juvenile distribution and growth of Patagonian toothfish around South Georgia

Early stages of toothfish are reported from cruises between 1978 and 2001. South Georgia was regularly sampled, Shag Rocks was briefly sampled in three summers, and Burdwood Bank was sampled in 1997. Most samples were using 8 m2 and 1 m2 nets in the upper 250 m and upper 3 m, respectively. Forty-three pelagic larval/early juvenile stages between 18.2 and 63 mm standard length (Ls) were taken between December and March. Four specimens were taken at Burdwood Bank, one at Shag Rocks, and 38 at South Georgia. Forty fish were from the upper 250 m, and 23 from the upper 3 m. They occurred onshelf and offshore over water depths between 10 and 3000 m. Estimated growth rate, at South Georgia from 11 cohorts (including published data), is c. 1% Ls, d−1 (n = 39). From this and a hatch size of 15 mm Ls, the predicted hatching season is November to mid-December. From seven trawl surveys during summer at South Georgia and Shag Rocks between 1986 and 2000, the mean depth of the smaller demersal juveniles 13–25 cm total length (LT) was &lt; 140 m, indicating that early juveniles probably migrate inshore.

Do some like it hot? Temperature as a possible determinant of variability in the growth of the Patagonian squid, Loligo gahi (Cephalopoda: Loliginidae)

Loligo gahi were collected from bottom trawl samples taken around the Falkland Islands on both commercial and research vessels from January 1994 to November 1995. Commercial samples were taken from both seasons of the fishery (February–May, August–October), research samples were taken in January, June and November. A sub-sample of squid was taken from each sample to provide statoliths for age determination by statolith increment analysis. Sea surface temperature data were derived for an area encompassing the southerly portion of the fishing grounds for L. gahi to provide an indicator of seasonal temperature variations for that region. Age data were derived for 486 females and 445 males. Exponential and power growth models explained the fit to the size-at-age data to a similar extent. Age data were grouped by month and by season of hatch to test the hypothesis that seasonal temperature variability influences the size-at-age relationship in L. gahi. Analyses of covariance showed that the relationships of both predicted mean mantle length and predicted mean body mass per month of hatch, and per season of hatch resembled closely the trends in mean monthly sea surface temperature, with the squid hatched in the summer, i.e., at higher temperatures, being significantly larger than squid of the same age but hatched in the winter months. The growth rates for adult squid in this study were similar over the age range analysed. This study provides evidence that increased temperature during a squid’s early growth period may accelerate growth markedly giving rise to significant differences in size-at-age for adult squid hatched at different temperatures.

Feeding of larval blue whiting and Atlantic mackerel: a comparison of foraging strategies

Fish larvae employ different feeding strategies depending on area and season of spawning and hatching of larvae. Feeding and growth of larvae of blue whiting Micromesistius poutassou and mackerel Scomber scombrus from Porcupine Bank and the Celtic Shelf Break, west of Ireland, were compared based on prey concentrations in the environment and larval feeding behaviour. Both species were adapted to different environmental conditions. The mesopelagic blue whiting spawned in oceanic water that was well mixed. It was characterized by low production and low prey densities with minimum prey densities &lt;1.0 organism 1−1. Larvae of the Atlantic mackerel hatched later in the season in more productive water that was well stratified. Prey densities in the mackerel environment reached up to 1001−1. Blue whiting larvae displayed a rather random distribution in the water column. Mackerel larvae &lt;7 mm standard length (Ls) were concentrated above the thermocline, while larvae &gt;7 mm traversed the thermocline into deeper layers. Mackerel larvae &gt;5mm Ls displayed marked cannibalism, exceeding 70%. Daily ration calculated on the basis of gut contents was rather low in both species: between 2.6 and 5.0% in blue whiting, but only 0.6 to 5.4% in mackerel. The results are discussed in relation to the respective environment both species encounter during their early larval life.

Age and growth of the short-finned squidIllex coindetiiin Galician waters (NW Spain) based on statolith analysis

Age and growth of Illex coindetii in the fishery northwest of Spain were estimated from statolith growth increments. 341 statoliths were examined (170 males, 171 females) from individuals of 48–379 mm mantle length (ML). The maximum size of squids was 279 mm ML for males and 379 mm ML for females. Weight-at-length of mature males was greater than that of immature males and mature and immature females. Lifespan was estimated at 13 months for males and 15 months for females. Recruitment to the fishery occurred approximately at three months of age. Mantle length instantaneous relative growth rates were 0.72 mm d−1 for males and 0.84 mm d−1 for females. Weight growth rate was 2.22 g d−1 for males and 3.66 g d−1 for females. Maturity stages, however, influenced increase in weight in both sexes, such that weight-at-age was greater for mature than for immature individuals. The age at which individuals mature is variable, ranging from 140 to 271 d in males and between 183 and 285 in females. Growth rates in both sexes were dependent on the season of hatching. Squids hatched in winter attained larger sizes for the same age than squids in other seasons. These seasonal differences in growth were only evident after squids had reached 8 months of age. Reading daily increments in statoliths seems to be a reliable technique for studying the age and growth of Illex coindetii.

Otolith structural and chemical analyses: the key to resolving age and growth of the Antarctic silverfish, Pleuragramma antarcticum

The various life history stages of the Weddell Sea population of Pleuragramma antarcticum were sampled to investigate life-history patterns of this ecologically important polar fish. Otoliths were examined for size, morphology and microstructure. Age determination of Antarctic fishes has proved to be difficult because of small ambient temperature fluctuations. External and internal examination of otoliths by scanning electron microscopy revealed internal increments (assumed to be daily) and hatching marks. Back calculation of hatching dates from otolith increments, suggested a hatching season from September-November, with recruitment to the adult population at three to five years of age. Growth data conformed well to the von Bertalanffy equation. Fish grew slowly, with the largest fish attaining ages of more than 30 years. A multivariate mathematical model relating age to otolith morphometrics and fish size proved reliable, making it possible to age large sample sizes of fish. Limited elemental microprobe data obtained from two otoliths demonstrated patterns which may be useful in indicating the environmental life history of individual fish. These collective data suggest that the ecological importance of populations of Pleuragramma antarcticum is most likely due to a long life span and high lifetime reproduction rate.

Growth of nestling Hamerkops Scopus umbretta in central Mali

Data on growth of nestling Hamerkops Scopus umbretta were analysed with respect to year and season of hatching and to hatch sequence. Quantitative growth characters included weight, culmen, tarsus, tail, third outermost primary quill, standard wing‐length and wing span. The growth constant K of weight was 0·179 and time t10–t90 was 21·8 days. Least‐squares analyses showed differences in weight gain, culmen‐length and tarsus‐length related to year and month but not to sequence of hatching. Predictive equations for character against age are provided for all linear measurements. Characters which attained apparent asymptotes before fledging were weight and culmen and tarsus‐length whilst other characters varied between 80 and 90% of reported adult size. Qualitative indications of growth discussed are crest development, colouration and the disappearance of the egg‐tooth. The rainy and post‐rains seasons appear to offer the Hamerkop the best chances of successful breeding and maximum growth rates.

Growth of nestling Hamerkops Scopus umbretta in central Mali

Data on growth of nestling Hamerkops Scopus umbretto were analysed with respect to year and season of hatching and to hatch sequence. Quantitative growth characters included weight, culmen, tarsus, tail, third outermost primary quill, standard wing‐length and wing span. The growth constant K of weight was 0.179 and time t10‐t90 was 21.8 days. Least‐squares analyses showed differences in weight gain, culmenlength and tarsus‐length related to year and month but not to sequence of hatching. Predictive equations for character against age are provided for all linear measurements. Characters which attained apparent asymptotes before fledging were weight and culmen and tarsus‐length whilst other characters varied between 80 and 90% of reported adult size. Qualitative indications of growth discussed are crest development, colouration and the disappearance of the egg‐tooth. The rainy and post‐rains seasons appear to offer the Hamerkop the best chances of successful breeding and maximum growth rates.