Nazca booby

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Description[edit]

Nazca booby
Nazca-Booby.jpg
Adult on Española Island, Galapagos Islands
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Suliformes
Family: Sulidae
Genus: Sula
Species: S. granti
Binomial name
Sula granti
Rothschild, 1902


The Nazca booby is a sea bird that form colonies on the islands it inhabits. It has a yellow iris, orange and pinkish beak, black facial skin in the form of a mask, and grey feet. Adults present white plumage with black tips of the wings and tail. The show sexual dimorphism, The female is bigger and heavier than the male, their beaks present a very slight difference in coloration, and the female squawk while the mail whistles.The chicks stay in the nests for a long period of time, and their coloration is snow white and fluffy. When they make their first attempts to fly their feather coloration change to grey as well as their beak and feet[2]. They nest near cliffs in bare terrains with little to no vegetation. Their nests are done on the bare floor.They are pelagic when they are out of their islands where they nest[3].

Filogenetics[edit]

They where previously in the order of the Pelecaniformes, however they where rescently placed in the Suliformes order, in the Sulidae family along with other 8 genres with 55 species[4]. Because of their similarity with the masked boobies (Sula dactylatra) they where considered as members of the same species, however, further studies that looked to difernciate the b-citocrome showed the existance of three different species: Nazca boobies, Central and oriental Pacific masked boobies, and Caribean and Atlantic masked boobies. This groups are likely to have diverged in a short period of time, 400.000-500.000 years ago[5].

Distribution[edit]

They are found in the oriental pacific from the islands in Baja California to the Galápagos islands and the Isla de la Plata in Ecuador and Mapaleo in Colombia[6][7].

Feeding[edit]

They feed by diving at high speed into the ocean and catching their prey, they mostly catch sardines, however they are known to also feed on flying fish, anchovies and squid, specially during the El Niño season [8]. Because of their sexual dimorphism females tend to feed on bigger prey and dive deeper[9].

Reproduction[edit]

This birds have relatively long lives, with a low annual reproduction and long periods of development on their Young. They tend to set their colonies in areas near or on cliffs, where the male will choose a territory to courtship the female, reproduce and care for their chicks[10].

When the female is ready to lay eggs, she starts incubating, time during which the parents control the different factors that are involved in the development of the embryo, such as temperature. In other species this is accomplished thanks to the incubation patch, a layer of bare skin that allows birds to transmit heat into their eggs, however Pelecaniformes, group that includes the boobies, don’t have this characteristic. Sula granti transfer the heat on to the eggs thru the interdactile membrane that helps it swim, this membrane is very vascularized, especially during the nesting period in addition to the heat they will transfer thru their breast[11]. Both the male and the female show parental care, in a biparental care[12]. The nesting size is one or two eggs, due to the low hatching success, however when 2 eggs are laid and they both hatch, it is common for only one of the chicks to survive. Usually the chick that hatches first is bigger and some hormonal triggers aggressively towards its sibling, this guarantees its success over the younger one which is pushed from the nest, and therefor is not fed and dies[13]. The energy investment on the parent’s part is very high, so their metabolic rates change during the nesting season (Apanius et al. 2008) this produces both parents to loose similar amounts of body weight and a decline on the effectivity of their immune system[12]

When there is no nesting season the parents show no energetic decline, this happens when the nesting conditions are not ideal, and this is crucial for the parents survival. A huge factor for the reproduction of Sula granti is the movement of sea currents, this cuases climate and weather changes. El Niño for example causes less aviabilty of food for sea birds, which causes them to migrate further south or north, change their diets or even stop a nesting process[8].

Conservation[edit]

Both in the UICN red list and the BirdLife International list of endagered species, Sula granti is considered of least concern (LC). All tho a population tendency to decrease is observable, this doesnt happen at a rate fast enough to cause concern, Some of the factors that influence the decrease of populations are over fishing and ocean contamination that has been reported[8][14]

References[edit]

  1. ^ BirdLife International (2012). "Sula granti". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ Ridgely, R. S. y P.J. Greenfield (2006). Aves del Ecuador. Guía de Campo. Fundación de Conservación Jocotoco. p. 92.
  3. ^ Friesen, V. L.; Anderson, D. J.; Steeves, T. E.; Jones, H.; Schreiber, E. A. (2002-01-01). "Molecular Support for Species Status of the Nazca Booby (Sula granti)". The Auk. 119 (3): 820–826. doi:10.2307/4089981. 
  4. ^ Wenny, Daniel G.; Devault, Travis L.; Johnson, Matthew D.; Kelly, Dave; Sekercioglu, Cagan H.; Tomback, Diana F.; Whelan, Christopher J. (2011-01-01). "The Need to Quantify Ecosystem Services Provided By Birds". The Auk. 128 (1): 1–14. doi:10.1525/auk.2011.10248. ISSN 0004-8038. 
  5. ^ Friesen, V. L.; Anderson, D. J.; Steeves, T. E.; Jones, H.; Schreiber, E. A. (2002-01-01). "Molecular Support for Species Status of the Nazca Booby (Sula granti)". The Auk. 119 (3): 820–826. doi:10.2307/4089981. 
  6. ^ "Nazca Booby (Sula granti) - BirdLife species factsheet". www.birdlife.org. Retrieved 2016-10-01. 
  7. ^ Pitman, Robert L.; Jehl, Joseph R.; Joseph L. Jehl, Jr. (1998-01-01). "Geographic Variation and Reassessment of Species Limits in the "Masked" Boobies of the Eastern Pacific Ocean". The Wilson Bulletin. 110 (2): 155–170. 
  8. ^ a b c Crawford, R. J. M.; Goya, E.; Roux, J.-P.; Zavalaga, C. B. (2006-11-01). "Comparison of assemblages and some life-history traits of seabirds in the Humboldt and Benguela systems". African Journal of Marine Science. 28 (3-4): 553–560. doi:10.2989/18142320609504205. ISSN 1814-232X. 
  9. ^ García-R, Silvana; López-Victoria, Mateo (2008-12-15). "Sexual differences in body size and diet in the Nazca Booby (Sula granti)" (7). ISSN 1794-0915. 
  10. ^ Maness, Terri J.; Westbrock, Mark A.; Anderson, David J. (2007-01-01). "Ontogenic Sex Ratio Variation in Nazca Boobies Ends in Male-Biased Adult Sex Ratio". Waterbirds: The International Journal of Waterbird Biology. 30 (1): 10–16. 
  11. ^ Morgan, Stephanie M.; Ashley‐Ross, Miriam A.; Anderson, David J. (2003-05-01). "Foot‐Mediated Incubation: Nazca Booby (Sula granti) Feet as Surrogate Brood Patches". Physiological and Biochemical Zoology. 76 (3): 360–366. doi:10.1086/375430. ISSN 1522-2152. 
  12. ^ a b Maness, Terri J.; Anderson, David J. (2007-01-01). "Serial Monogamy and Sex Ratio Bias in Nazca Boobies". Proceedings: Biological Sciences. 274 (1621): 2047–2054. 
  13. ^ Tarlow, Elisa M; Wikelski, Martin; Anderson, David J (2001-08-01). "Hormonal Correlates of Siblicide in Galápagos Nazca Boobies". Hormones and Behavior. 40 (1): 14–20. doi:10.1006/hbeh.2001.1661. 
  14. ^ Takasuka, Akinori; Oozeki, Yoshioki; Aoki, Ichiro (2007-05-01). "Optimal growth temperature hypothesis: Why do anchovy flourish and sardine collapse or vice versa under the same ocean regime?". Canadian Journal of Fisheries and Aquatic Sciences. 64 (5): 768–776. doi:10.1139/f07-052. ISSN 0706-652X.