Short Note Additional Reports on the Breeding Ecology of Chabert s Vanga Leptopterus chabert and Red-tailed Vanga Calicalicus madagascariensis

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1 J. Yamashina Inst. Breeding Ornithol. 45: Ecology 53 58, of Chabert s 2013 and Red-tailed Vangas Yamashina Institute for Ornithology 53 Short Note Additional Reports on the Breeding Ecology of Chabert s Vanga Leptopterus chabert and Red-tailed Vanga Calicalicus madagascariensis Masahiko Nakamura*, Rija Sylvain Rakotosoa** and Hajanirina Rakotomanana** Abstract. The Vangidae, an endemic family in Madagascar, provides one of the most striking examples of adaptive radiation. However, basic information on the breeding biology of each species is still lacking. To provide additional information on the clutch size of the Chabert s Vanga Leptopterus chabert and on the mating system of the Red-tailed Vanga Calicalicus madagascariensis, we studied the breeding ecology of these two species in southwestern Madagascar between October and November, The clutch size for Chabert s Vanga was 3 or 4 (n 5 nests). Both mates of the Red-tailed Vanga shared duties in egg incubation and brooding, and delivered insects to the nestlings in the single observed nest. These results suggest that the Red-tailed Vanga is a socially monogamous species. Key words: Clutch size, Mating system, Parental care. Introduction The family Vangidae is endemic to Madagascar and consists of 21 species (Reddy et al. 2012, Jønsson et al. 2012). The vangids are best known for their adaptive radiation, which is comparable to that of the Galapagos finches or of the Hawaiian honeycreepers (Grant & Grant 2008, Reddy et al. 2012, Jønsson et al. 2012). Although the evolutionary history of the vangids has been well studied (Yamagishi & Nakamura 2009), basic information on the breeding biology of each species is still lacking. Our research team previously reported on the breeding ecology of the Chabert s Vanga Leptopterus chabert (Nakamura et al. 2009), but were able to confirm the clutch size of only one nest because nest trees were too high to examine the nest contents. A study of the Redtailed Vanga Calicalicus madagascariensis by our team was also able to access only one nest (Rakotomanana et al. 2009). Thus, additional information is needed on these species to fully describe their breeding systems. In this note we report our observations of the two vanga species at Ifaty in southwestern Madagascar. The aims of this study were: (1) to provide more information on the clutch size of Received 4 September 2012, Revised 11 March 2013, 2nd Revision 28 April 2013, Accepted 2 May * Laboratory of Animal Ecology, Department of Biology, Joetsu University of Education, 1 Yamayashiki- Machi, Joetsu-Shi, Niigata , Japan. masahiko@juen.ac.jp ** Department of Animal Biology, Faculty of Science, University of Antananarivo, Antananarivo 101, Madagascar. 53

2 54 Masahiko Nakamura, Rija Sylvain Rakotosoa and Hajanirina Rakotomanana Chabert s Vangas, and (2) to evaluate the type of breeding system from perspective of the parental investment of male and female Red-tailed Vangas. Methods This study was conducted in dry forest at Mangily (23 07 S, E, m alt.), Ifaty, about 22 km north of Toliara in the Atsimo Andrefana Region during October and November in This spiny forest is dominated by trees of the family Didiereaceae and of the genus Euphorbia. Two species of baobab Adansonia rubrostipa and A. za are abundant in the forest. The climate is sub-arid with an annual rainfall of only mm and an annual mean temperature about 25.2 C (Moat & Smith 2007). There are many trails in the forest. To find the nests, we walked along them at random from 0500 to 1000 every day. When we located nests, we identified the nest tree species. Nest height above the ground was measured along with the trunk diameter at breast height (DBH). To observe the contents of nests, we used a telescopic pole made of carbon fiber (DCF- 1000, DENSAN). The pole could extend from 69 cm to 10 m. We attached a compact digital camera on the top of the pole and extended the pole above the nest to film the nest contents. To examine the relative contributions of the sexes to reproductive efforts of Red-tailed Vangas, we studied the following activities: (1) the time budget of incubation (percentage of time that individuals spent incubating to total observation time for each day), (2) the time budget of brooding (percentage of time that individuals spent brooding to total observation time for each day), (3) feeding frequency (time/hour/brood), and (4) type and number of prey items delivered to nestlings. An incubation session was defined as having started when a focal individual began incubating eggs, and was considered to have ended when that individual left the nest. Similarly, a brooding session was defined as having started when a focal individual began brooding the nestlings, and was considered to have ended when that individual left the nest. If a parent stayed for more than two minutes in the nest with its hatched young, we defined this behavior as brooding. Nests were visited at two-day intervals to examine their status. Direct observations were made using a 30 spotting scope, and indirect observations were made with a SONY video Hi8 camera (CCD-TRV96), from a vantage point that allowed a good view of the nest (5 15 m). Direct and indirect observations were usually made between 0500 and 1200 for six hours each day. Data from both direct (20 hours) and indirect observations (58 hours) were combined for the analysis. We did not attach colored leg rings to the pairs in order not to disturb their breeding behavior. However, we were able to recognize the mates attending their nest based on variation in their plumage color: the male had white plumage in the right greater coverts and female had a small black patch on the throat. Results and Discussion Chabert s Vanga We found nine nests (A I), five of which (A, B, E, G and I) contained three or four eggs

3 Breeding Ecology of Chabert s and Red-tailed Vangas 55 Table 1. Summary of clutch size, nest tree (scientific name), nest height (above the ground), and DBH (Diameter at breast height) of nest tree at nine nests of Chabert s Vangas. Date means day when nest was discovered. Nest Study year Date Clutch size Nest tree (Family name) Height (m) DBH (cm) A Nov. 3 Adansonia rubrostipa (Malvaceae) B Nov. 3 Givotia madagascariensis (Euphorbiaceae) C Nov. Givotia madagascariensis (Euphorbiaceae) D Nov. Delonix decaryi (Fabaceae) E Nov. 4 Givotia madagascariensis (Euphorbiaceae) F Oct. Adansonia rubrostipa (Malvaceae) G Oct. 4 Adansonia rubrostipa (Malvaceae) H Oct. Adansonia rubrostipa (Malvaceae) I Nov. 3 Adansonia rubrostipa (Malvaceae) (Table 1). When we found the five nests, the parents had already incubated the eggs. Incubation duties were shared between two adults at each of the five nests. All eggs were lost from the nests prior to hatching. The clutch size of our study site was larger than the two (Appert 1970) or three (Langrand 1990, Nakamura et al. 2009) reported elsewhere, but we did not know the reason. For the other four nests (C, D, F and H), the parents made nests but abandoned them thereafter. Red-tailed Vanga We found one nest on 4 October 2011, and the parents had already incubated three eggs. The nest was built on the branch of a baobab tree (A. rubrostipa). The nest was bowl-shaped and consisted of lichens and vegetable fibers, covered with spider webs. Nest height and DBH were 723 cm and 207 cm, respectively. The exterior and interior diameter of the nest was 75 mm and 50 mm, respectively. The exterior depth was 58 mm and the interior depth was 45 mm. Both male and female took turns incubating, spending a total of ( SE, n 5 days) of their time (Fig. 1). Incubation sessions ( SE) of the male averaged min (Range: , n 24), and that of the female averaged min (Range: , n 23). The difference in duration between incubation sessions of the two sexes was not significant (z 1.77, P 0.08, Mann-Whitney U-test). We considered that the eggs hatched on 14 October, because the brooding female ate eggshell and the parents started to provide food to their nestlings on the date. Thus, their incubation period lasted for more than 10 days. In a previous study (Rakotomanana et al. 2009) incubation lasted about 24 days. Both the male and the female brooded the nestlings (Fig. 2). However, brooding activity decreased with the growth of nestlings (Fig. 2). Both members of the pair brought food to their nestlings during the nestling period (Fig. 3). The feeding frequency increased with nestling age, but decreased after the chicks had reached 15 days old (28 October, Fig. 3). All three nestlings fledged on the afternoon of October 28th. Thus, the nestling period lasted for 15 days, a finding identical with that of Rakotomanana et al. (2009). It was difficult to identify the food items provided to the nestlings from 14 to 18 October because the parents usually masticated the food before offering it to their nestlings and be-

4 56 Masahiko Nakamura, Rija Sylvain Rakotosoa and Hajanirina Rakotomanana Fig. 1. Incubation time budgets of male (open circle), female (solid circle) and total (open square). Observations were made for six hours each day. Fig. 2. Brooding time budgets of male (open circle) and female (solid circle). Observations were made for six hours in each day. Fig. 3. Feeding frequency (time/hour/brood) of male (open circle) and female (solid circle) Red-tailed Vanga. Observations were made for six hours each day.

5 Breeding Ecology of Chabert s and Red-tailed Vangas 57 Table 2. Prey delivered by the Red-tailed Vanga. Prey items were recorded during the nestling period. Prey (Order or Family) Number Percentage Caterpillar of Geometridae (Lepidoptera) Stick insects (Phasmatidae) Fly (Muscidae) Other caterpillars (Lepidoptera) Moth (Lepidoptera) Spider (Aranea) Gadfly (Diptera) Dragonfly (Odonata) Beetle (Coleoptera) Butterfly (Lepidoptera) Wasp (Hymenoptera) Grasshopper (Acrididae) Mantis (Mantidae) Cicada (Cicadidae) Mosquito (Diptera) Unidentified prey Total cause feeding was very rapid. Therefore, we instead analyzed only food items from 20 to 28 October, and recorded 313 prey items (Table 2). Caterpillars of the family Geometridae, stick insects and flies were the main prey, accounting for 61.9 of the 260 items identified (Table 2). Most prey items were smaller than the adult s bill length (10.5 mm, Rakotomanana et al. 2009). However, the body length of stick insects and geometrid caterpillars was over 5 cm. Rakotomanana et al. (2009) concluded that the mating system of the Red-tailed Vanga could be monogamous because both mates shared duties in egg incubation, brooding and caring for the young. The findings of the present study were identical; both mates incubated eggs (Fig. 1), brooded nestlings (Fig. 2) and gave insects to nestlings (Fig. 3, Table 2). During the breeding period, the mates were not aided by any helpers. These results suggest that the Redtailed Vanga is a socially monogamous species. Acknowledgements This study would have not been possible without the help of guides, Mosa and his family, at Mangily Forest. Mr. Ravomiarana Ranaivosolo helped identify the prey items. We also express our thanks to Dr. Richard Jenkins for his many constructive comments and suggestions. This study was supported by a Grant-in-Aid for Scientific Research (B) from the Japan Society for the Promotion of Science to MN (No ). References Appert, O Zur Biologie der Vangawürger (Vangidae) Südwest-Madagaskars. Ornithologische Beobachter 67: Grant, P. R. & Grant, B. R How and Why Species Multiply: The Radiation of Darwin s Finches. Princeton University Press, Princeton.

6 58 Masahiko Nakamura, Rija Sylvain Rakotosoa and Hajanirina Rakotomanana Jønsson, K. A., Fabre P.-H., Fritz, S. A., Etienne, R. S., Ricklefs, R. E., Jørgensen, T. B., Fjeldsa, J., Rahbek, C., Ericson, P. G. P., Woog, F., Pasquet, E. & Irestedt, M Ecological and evolutionary determinants for the adaptive radiation of the Madagascan vangas. Proceedings of the National Academy of Sciences 109: Langrand, O Guide to the Birds of Madagascar. Yale University Press, New Haven and London. Moat, J. & Smith, P Forêt sèche épineuse dégradé du sud-ouest. In Atlas des Vegetations de Madagascar (ed. M. Payne), pp Royal Botanic Gardens, Kew Richmond Surrey, England. Nakamura, M., Okamiya, T., Hasegawa, M. & Hasegawa, M Cooperative breeding in the endemic Madagascan Chabert s Vanga Leptopterus chabert. Ornithological Science 8: Rakotomanana, H., Tateno, M. & Nakamura, M Breeding ecology of the Malagasy endemic Red-tailed Vanga Calicalicus madagascariensis. Ornithological Science 8: Reddy, S., Driskell, A., Rabosky, D. L., Hackett, S. J. & Schulenberg, T. S Diversification and the adaptive radiation of the vangas of Madagascar. Proceeding of the Royal Society B 279: Yamaghishi, S. & Nakamura, M Family VANGIDAE (VANGAS). In Handbook of the Birds of the World, Vol. 14 (eds. J. del Hoyo, A. Elliott & D. Christie), pp Lynx Edicions, Barcelona Leptopterus chabert Calicalicus madagascariensis R. S. Rakotosoa, H. Rakotomanana: Department of Animal Biology, Faculty of Science, University of Antananarivo, Antananarivo 101, Madagascar.