Parental egg destruction - Part 1: My thoughts on Lady Chiak Nung

My earlier attempts a couple of years ago to breed from Lady Chiak Nung had failed miserably due to her post-laying destructive behavior. In spite of these past failures, I have not given up on my hope to breed for certain desirable traits from her, hence a final attempt to breed her was included in our breeding plan for this year. She is to be paired up with our foundation stud bird, Funkie. This decision to risk Funkie's precious breeding time for the season, on a female with such disappointing breeding records, was further justified by my quest for a better understanding of her counter-productive breeding behaviour as well as my wish to see if this behavioral abnormality can be reversed. The cut-off point for Funkie's loss of breeding time for the season was set to be for no more than 2 failed clutches from this pairing, after which, he will have to be paired up with another proven female and the attempt will be considered to have failed.

From experience, egg destruction and infanticide by both sexes of this species is not uncommon. Some of us may be of the opinion that these destructive behaviours are due to hormonal fluctuations, triggered by external factors such as a perceived threat in the immediate vicinity, causing the parental hormones to be imbalanced. In most cases of parental egg destruction or infanticide, the above reasoning is logical, especially if environmental triggers are observed to be present. However, this may not be the case with Lady CN. In every instance that she had entered the nestbox to lay and after the usual time required to lay the egg, she would without fail, exit the nest with the freshly laid egg between the beaks, only for it to be immediately destroyed on the cage floor. She will also always consume part of the contents and almost all of the shell and all these without even the slightest of provocation. This is not the same as having laid a few eggs over the course of a few days and then succumbing to the sudden emergence of an environmental threat or challenge.

In the case with Lady CN, they were all immediate post-laying destructions and in every of her case, there was no obvious triggers observed to be present at the moment of destruction. There was also no visible or audible signs of excitement from both birds, before and after each exhibition of the behaviour, further indicating that there was an absence of an external trigger. Furthermore, there was hardly any time-lag between completion of laying and commencement of destruction to allow for a trigger to take place.

The eggs were not simply thrown out of the nest as commonly observed but instead, each was deliberately brought down to the cage floor to be consumed. However, there is also no reason to believe that the egg-consuming part of the behaviour is of a resource saving nature to recover part of the invested nutrients, since there was never any hint of imminent danger to incite abandonment of the nest.



...to be continued