I observed two interesting behaviours by Black-thighed Falconets (Microhierax fringillarius). today in the city. This is a family of four birds, two of which behaved like younger (first year adult) birds. The first behaviour is seen in the image below.
One of the birds plucked a dried winged seed/fruit from an Angsana tree (Pterocarpus indicus) and flew over to where two other Black-thighed Falconets were located. The item was not offered to the other and was then dropped without retrieving it; possibly because both my wife and I were observing the closely bird. This behaviour is not recorded in Ferguson-Lees & Christie (2001); they mention that the only material used to line nests are insect remains.
In trying to understand this behaviour I looked back at data I had previously read on leaf presentation as possible courtship behaviour in other falconet species. The dried winged seed from the Angsana tree is very much like a leaf. Allen, Holt & Hornbuckle (2002) discuss leaf presenting as a possible courtship behaviour when observing Pied Falconets (Microhierax Melanoleucos). Naoroji (1977) was the first to record such behaviour in Collared Falconet (Microhierax caerulescens). There are some lovely images of this behaviour by Pied Falconet (Microhierax melanoleucos) taken by Wang LiQiang (Crew 2018).
Since two of the five Microhierax species show this behaviour, it is reasonable to consider similar courtship behaviour for what we observed in the Black-thighed Falconet. Leaves offered are usually dried leaves. No one has been able to offer an explanation for this behaviour as the leaves are not usually used to line nests. Offering food items as part of the courtship ritual would have more expected.
- James Ferguson-Lees, David A. Christie. Raptors of the World. Christopher Helm. 2001
- Desmond Allen, Paul Holt, Jon Hornbuckle. Leaf presenting As Possible Courtship Behaviour by Pied Falconets Microhierax Melanoleucos. The journal of the Bombay Natural History Society. 2002; Volume 99: 518-520. (available here: https://www.biodiversitylibrary.org/part/155760#/summary)
- Bec Crew. We need to talk about tiny falconets. Australian Geographic. 2018 (available here: https://www.australiangeographic.com.au/blogs/creatura-blog/2018/10/we-need-to-talk-about-tiny-falconets/)
Amar-Singh HSS (Dato’ Dr)
Ipoh, Perak, Malaysia
Location: Ipoh City, Perak, Malaysia
Habitat: Urban city environment
Date: 26th October 2019
Equipment: Nikon D500 SLR with Nikon AF-S Nikkor 500mm f/5.6E PF ED VR, handheld