The Sickle-billed Vanga (Falculea palliata)

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From the fantastically diverse vanga family (vangidae) the sickle-billed vanga really is sight to behold.  When a species has a bill as distinctive as this you can see why it would be quick to identify on #BeakoftheWeek, and low and behold the bird that the bill belonged to was quickly ascertained in the weekly challenge. Some of the beaks we have had the opportunity to scan at the Natural History Museum collections in Tring are a joy to work with, and this was definitely one of those.

Here is a nice video from the internet bird collection for you to watch to get a feel for what this bird looks like and how it moves.

 

  • What does it look like?

    The sickle-billed vanga is the largest in its family and it really stands out because of the strongly decurved bill that is possesses. There is no sexual dimorphism in this species, with both males and females being mostly white except for its upperparts, which are black with a blue sheen (as can be seen below). These vangas have blackish-brown irises, its legs are dark grey/pale blue and its bill is bluish grey fading to ivory at the tip.  Juveniles are similar in appearance to adults.

    sickle-billed vanga 2

    Sickle-billed vanga

    This is all very well and good if you can see the bird, but what if it is doing what birds are wont to do and hiding just out of sight? Well then we can rely on what it sounds like, if it decides to make any sound that is. Below is a recording of this species in the wild for you to memorise if you happen to be heading out to Madagascar.

  • Where can you find this bird?

    This species is endemic to Madagascar and is a year round resident along the whole of the western side of the island nation, as can be seen below. They are typically found in dry deciduous forests and Savannah.

    Sickle-billed Vanga range

    Sickle-billed Vanga range

  • Diet

    This species forages in holes and crevices of living and dead trees on the hunt for invertebrates (such as spiders, beetles and cockroaches) and small vertebrates (e.g. geckos). In the non-breeding season they form large foraging groups of between 20-30 individuals and sometimes form mixed groups with other species such as Madagascar Crested Drongos (Dicrurus forficatus).

    Sickle-billed Vanga

    Sickle-billed Vanga

    Breeding

    These vangas breed between October and January in NW Madagascar. Interestingly they are Polyandrous, where more than one male mates with one female and all the males (plus the female) then feed the young. These modern males also help with predator defence, territorial defence and sometimes incubation and brooding.

    This nest itself is built 9-16m off the ground in the fork of a tree and is formed from twigs into a cup-shape before being lined with more comfortable materials. Once it is ready a clutch of 3-4 eggs will be laid, which will then be incubated for 16-18 days. The chicks will then remain in the nest for 19-23 days before entering into the real world.

  • Good news on this front in that this species is seen as of “At Least Concern” on the IUCN Redlist for species. It is common to fairly common across it’s large range and it also found in many protected areas.

  • Sickle-billed vangas are polyandrous, as mentioned previously, which is a rare mating system thought to only occur in less than one percent of bird species. It is well documented in phalaropes, although this “strange” mating system did lead to John James Audubon mislabelling all of his males and female phalaropes in his illustrations.

    There are two types of polyandry: Sequential polyandry is where a female mates with a male, lays eggs and then leaves the male to do the rest as she goes off to find another male to mate with, and Simultaneous polyandry, where a female holds a large territory which contains numerous smaller nesting territories where males care for the eggs and young.

    For further reading this week I am providing a link that will explain polyandry in more detail and also provides links to information on different mating systems, such as polygyny and cooperative breeding. Follow this link to a Stanford University site to begin your learning journey.

References

BirdLife International (2016) Species factsheet: Falculea palliata. Downloaded from http://www.birdlife.org on 26/08/2016.

BirdLife International. 2012. Falculea palliata. The IUCN Red List of Threatened Species 2012: e.T22708041A39344831. http://dx.doi.org/10.2305/IUCN.UK.2012-1.RLTS.T22708041A39344831.en. Downloaded on 25 August 2016.

Yamagishi, S. & Nakamura, M. (2016). Sickle-billed Vanga (Falculea palliata). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/60562 on 25 August 2016).

Images and Videos

BirdLife International and NatureServe (2014) Bird Species Distribution Maps of the World. 2012. Falculea palliata. The IUCN Red List of Threatened Species. Version 2016-1

ian_hempstead, IBC1195731. Accessible at hbw.com/ibc/1195731.

Keulemans’ Sickle-billed vanga by John Gerrard Keulemans is licensed Public Domain Mark 1.0.

Sickle-billed vanga by Cédric de Foucault is licensed under CC BY-NC-SA 4.0.

Audio

Hans Matheve, XC155300. Accessible at www.xeno-canto.org/155300.

The Wrybill (Anarhynchus frontalis)

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We decided that it would be nice for us to give you some information on the chosen #BeakoftheWeek, so we are kicking things off with last week’s…

wrybill 1

Figure 1. Wrybill beak bend

Being amongst the strangest beaks that we have encountered during our scanning escapades, the wrybill, or ngutuparore, is a charismatic species endemic to New Zealand.   You’ll notice straight away from this picture and Fig 1 that there is something slightly awry with the morphology of this birds beak.  It is unique in being the only species of bird that has its beak always bent laterally, and exclusively to the right.  This specially adapted beak is used to sweep under stones in its hunt for invertebrates, such as mayfly and caddisfly.

The internet bird collection has a nice video of some wrybills in action.

The wrybill is a pale plover, of about 20cm in length, from the charadriidae family, which consists of about 60 species including dotterels and lapwings.  Similar species include the sanderling and banded dotterel.  Its breeding grounds are found solely on the braided riverbeds of New Zealand’s South Island, from where it migrates to over wintering grounds in the North Island.   They are known to form dense flocks at their wintering grounds (see Fig.2).

 

Figure 3 A sketch of the Wrybill from A History of the Birds of New Zealand (1888)

Figure 2 A sketch of the Wrybill from the A History of the Birds of New Zealand (1888)

This monogamous, ground nesting species has a life expectancy of about 5 years.  Chicks are precocial and clutch size consists of two eggs on average.  There is slight sexual dimorphism, with males having a black bar above their foreheads and a black breast bar.  Females have a slightly browner and narrower breast bar and lack the bar above the forehead.

 

 

 

The wrybill employs a few techniques to avoid predation.  As you can see from this picture of their eggs they blend nicely into the background of the riverbed, similarly to the pale appearance of the adults.  Camouflage is not the only method used as parents will also perform distraction displays to entice predators away from their nests.

This is a species in decline, with the IUCN redlist describing them as vulnerable since 1994.  Before the 1940s hunting was a cause for a major drop in their population, which has since recovered.  However, threats from predation by introduced mammals and native birds, as well as the flooding of nests and the loss and degradation of breeding grounds, are further putting this species under threat.  Population estimates from winter counts lie at about 5,000 individuals.

To fully immerse yourself in the world of the wrybill you can check out a distribution map and listen to some wrybill calls on Xeno Canto.

References:

BirdLife International (2015) Species factsheet: Anarhynchus frontalis. Downloaded from http://www.birdlife.org on 05/05/2015.

Dowding, J.E. 2013. Wrybill. In Miskelly, C.M. (ed.) New Zealand Birds Onlinewww.nzbirdsonline.org.nz

Hay, J. R. 1984. The behavioural ecology of the wrybill plover. Dissertation. Ph.D., Auckland University, Auckland.

The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 05 May 2015.

Wiersma, P. (1996). Wrybill (Anarhynchus frontalis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/53856 on 5 May 2015).

Images

Sketch of Wrybill” by A History of the Birds of New Zealand, 1888 is licensed under Public Domain Mark 1.0.

Wrybill bill bend” by A History of the Birds of New Zealand, 1888 is licensed under CC BY-SA 3.0.