The grey-bellied cuckoo (Cacomantis passerinus) belongs to the family Cuculidae under the order Cuculiformes.
The species under genus Cacomantis are usually brown or slaty colored. The tails are graduated and barred. Most of them have round nostrils. Most of the Cacomantis spp. are obligate brood parasites, meaning that they only reproduce in this fashion.
The brood parasites lay their eggs in the nest of other birds and relying on the host to raise their young. The cuckoo egg hatches earlier than the host's. The growth-rate of the parasite chick is much faster than that of the host.
Further, Cacomantis spp. chick instinctively evict the eggs or young of the host species. The surviving host nestlings may starve to death due faster growth rate of the parasite nestling.
The parasite nestling's rapid begging call and the open mouth serves as a sign stimulus leading to host parents feeding the parasite chick more often.
 |
| 1.Grey-bellied cuckoo (Cacomantis passerinus) image by Vivekpuliyeri |
 |
| 2.Image by Sasidharanmanekkara |
 |
| 3.Image by Karunakar Rayker |
 |
| 4.Cacomantis passerinus image by Sarala Gamage |
 |
| 5.Image by J.M.Garg |
 |
| 6.Image by Thimindu Goonatillake |
 |
| 7.Grey-bellied cuckoo (Cacomantis passerinus) Image by Sarala Gamage |
1.Image source: https://commons.wikimedia.org/wiki/File:Grey-bellied_Cuckoo_2_@_Nilambur_1-2-14.jpg (cropped)
Author: Vivekpuliyeri | License: CC BY-SA 3.0
2.Image source: https://commons.wikimedia.org/wiki/File:Grey_bellied_cuckoo_male.jpg (cropped)
Author: Sasidharanmanekkara | License: CC BY-SA 4.0
3.Image source: https://www.flickr.com/photos/21932201@N04/2295984856 (cropped)
Author: Karunakar Rayker | License: CC BY 2.0 as on 4/4/17
4.Image source: https://commons.wikimedia.org/wiki/File:Grey-bellied_Cuckoo_(2).jpg (cropped)
Author: Sarala Gamage | License: CC BY-SA 3.0
5.Image source: https://commons.wikimedia.org/wiki/File:Grey-bellied_Cuckoo_(Cacomantis_passerinus)_in_Kinnarsani_WS,_AP_W_IMG_5863.jpg (cropped)
Author: J.M.Garg | License: CC BY-SA 3.0
6.Image source: https://www.flickr.com/photos/thimindu/5461671287/ (cropped)
Author: Thimindu Goonatillake | License: CC BY-SA 2.0 as on 4/4/17
7.Image source: https://commons.wikimedia.org/wiki/File:Grey-bellied_Cuckoo.jpg (cropped)
Author: Sarala Gamage | License: CC BY-SA 3.0
Current topic in Birds of India: Grey-bellied cuckoo (Cacomantis passerinus) images.