An unusual set of rictal bristles in Pied Fantail

On the morning of 8th November 2017, Asher Ang was out photographing birds when he returned with a scoop. This is what he wrote on Facebook:

“Last weekend a certain Pied Fantail followed my wife and I for a while, in order to scoop up insects taking flight when we walked. It stayed really close, and I got some tight shots. When my son looked at the photos, he saw [a morphological] part that I don’t know about. Please share if you know the answer. Thanks.”

The images above and below show the close-up image of the Pied Fantail (Rhipidura javanica). Between the right eye and the bill is what appears to be a “bear’s paw with 5 sharp claws”. There is a corresponding set on the left side of the bill but because of the positioning of the head, it does not show up as clear as that on the right. At first glance the structure looks like an abnormal growth.

Jeff Long was right when he identified it as rictal bristles and described its possible functions, joined by Clarence Khoo. Wayne Johnson’s LINK provided detailed information for those interested in wanting to know more of the functions of rictal bristles. More information can be obtained HERE.

Yes, the “bear’s paw” is actually rictal bristles. This was further confirmed by field ornithologist Wang Luan Keng. But so are the long bristles on either side of the bill – they are the normal rictal bristles that most people are familiar with.

According to Bole (2006), “Rictal bristles are a prominent characteristic of the family, and are often as long as the bill… the fantails are unusual in that they have a double row of bristles arising on both sides of the gape. One row is situated slightly in front of and below the orbit, the “normal” position in most flycatching species, and the other is below the base of the lower mandible.”

So, the Pied Fantail has two rows of rictal bristles, one whisker-like and the other “bear’s paw-like”. I have been successful in locating only one image from the internet that looks like Asher’s image HERE but unfortunate there is no name attached to the bird.

Asher’s image of the Pied Fantail showing the two types of rictal bristle may well be the first. Photographers would have difficulty capturing this unusual form of rictal bristles in their images unless they have an opportunity to be very close to the bird. Or if they are involved in mist netting of bird where they actually handle birds and photographs can be taken very close by.

Indeed, Asher’s image can be considered another BICA Moment.

Asher Ang & YC Wee
Singapore
4th December 2017

References:
1. Boles, W. E., 2006. Family Rhipiduridae (Fantails). In: del Hoyo, J., A. Elliott & D. A. Christie (eds.). Handbook of the birds of the world. Vol. 11. Old World Flycatchers to Old World Warblers. Lynx Editions, Barcelona. Pp. 200-242.
2. Cunningham, S. J., R.A. Maurice & I. Castro, 2011. Facial bristle feather histology and morphology in New Zealand birds: Implications for functions. Journal of Morphology, 272:118-128.

This post is a cooperative effort between Birds, Insects N Creatures Of Asia and BESG to bring the study of birds and their behavior through photography and videography to a wider audience.