Olive-backed Sunbird: Sibling rivalry

posted in: Feeding chicks, Sunbirds | 0
Both chicks appear at the nest entrance
Both chicks appear at the nest entrance

“It has been very fortunate for me that I had the opportunity to observe at very close range the nesting behavior of our Olive Backed Sunbird (Cinnyris jugularis, and it was for three nesting cycles. The first was in December 2016, whereby only one egg was laid and hatched, the second was in February 2017, whereby two eggs were laid and successfully hatched. The third nesting saw the two siblings successfully leaving the nest today, 12th May 2017.

Older chick covering younger siblings with both wings
Older chick covering younger siblings with both wings

“For the first two nesting no unusual aggressive behaviours were observed between the two siblings. It was not so with the third nesting. On the final days, the bigger of the chicks started to show aggressive and domineering behavior over the smaller and meeker sibling.

Older chick successfully covering younger sibling with its left wing
Older chick covering younger sibling with its left wing

“Just before the arrival of the parents bearing food for the chick, the parents would call from afar to announce their arrival. On hearing this, the two chicks would appear at the entrance of the nest to receive the food.

Adult at the nest with only older chick seen at the nest entrance
Adult at the nest with only older chick seen at the nest entrance

“You will notice that the meeker one has to fight to get itself noticed. However, in the second picture the dominant bird covered the other chick with his wing, preventing the parent bird from seeing the smaller chick, so that he gets the first pick of the morsel.”

K C Tsang
Singapore
12th May 2017

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