Abstract
Comparative studies on the Crimson (Neochmia phaeton) and Long-tailed Finches (Poephila acuticauda) are part of the ongoing research that seeks to determine the reason for the decline of the Gouldian Finch, Erythura chelobia, in the wild. This explains why I was sitting with my back to a white gum tree, binoculars glued to my eyes, recording crimson finch band colours. I had to record band colour combination, for example, w I b I l I F means white over black on the left leg and is a female. u/J means an unbanded juvenile, etc.
I had been given this job by Dr Sarah Legge, Australian Wildlife Conservancy's chief scientist, and I was recording a flock on a 40 metre stretch of dried up creek bed which contained two waterholes and was lined by the very prickly pandanus palm, a typical Crimson Finch habitat.
After a while I realised that what I was watching was a breeding colony. What I mean is it slowly dawned on me that all the breeding Crimsons I had ever seen in the wild had nested within close proximity to each other and were, therefore, true colony birds. This is completely distinct from the Gouldian, which is definitely not a colony bird. For example, a pair has been recorded nesting as far away as 17 km from the next nearest nest. This insight came as a bit of a revelation to me as everyone in aviculture knows the Crimson as an aggressive potential wife-killer that should never be kept in a colony!
Fascinated by this instead of doing my job, I began watching the social behaviour of the flock and using the band colour combination to sort out the flock pecking order. Within half an hour, I had sorted out which were the dominant pair and had a good handle on who were numbers two and three. It was quite interesting. The dominant cock was busy feeding nestlings and simply too busy to spend much time hassling his neighbours. But, every time he went down to forage, he would land next to another cock and do a cursory aggression display. The submissive cock didn't argue and just upped and moved about a metre or so away then carried on foraging. Interestingly, the dominant hen did exactly the same, but she always landed next to another female and this pattern was repeated down the pecking order throughout the flock.
When I discussed this with an American scientist who was doing the Crimson work, she confirmed my findings and explained the behaviour was standard "mate protection". Each male would protect his female from extra pair copulation or, in other words, stop the other cocks from "playing away" with his hen. She also said that she had been shocked when she started the project at the beginning of the breeding season and saw two cocks rolling round and round on the ground with feet locked. She was sure they were going to kill each other!
After this experience I began to think about my own breeding regime. Just before setting off to The Kimberley, I had lost two of my Crimson hens and just managed to save a third before her mate killed her. The latter pair was nesting but every time the hen came off the nest, the cock chased her round and round the cage until she went back on the nest. If he did not kill her outright she was going to die of starvation, as he would not give her time to eat or drink.
By now you may gather I was trying to breed in separate pairs and was gathering a surplus of cocks! Armed with my new knowledge, I thought I would try an experiment. I put three cocks and one hen in a well-brushed three metre by one and a half metre wide aviary. And the result? The cocks quickly sorted out who was boss and paired up with the hen. During one season they produced 23 juveniles before I broke the group up.
I repeated this pattern with other groups of four and had success with them, all with not a single hen or cock lost.
The behaviour was exactly what I had seen in the wild. The dominant cock would displace the extra males who would just move away. I think it worked better because there were two spare males and not one so the dominant cock could not harry one to his death. I also made sure there were multiple feeding points.
This season I am trying another experiment. I have put five pairs in a planted 10 meter square aviary which has a three and a half metre square shelter and feeding station attached. We hung eight nesting/roosting stations which contain three short perches and a wire basket for nesting in descending height down both sides of the aviary. They are configured to also act as weather shelters and to be easily defended against dominant cocks. This is the reason why the roof has a shiny, steeply, sloping metal plate that stops the dominant cocks from sitting on the top and threatening the residents roosting or nesting below.
Placing the nest boxes in a sharply descending order and having a shiny metal top is the same regime that we use in the research block of the Save the Gouldian Fund and is designed to minimise stress and aggression. Research has shown that the dominant pairs always take the higher positions and the dominant cock will try and defend all potential nesting sites that are on the same level.
Similarly, aggression or dominance is from above. The dominant cock would not approach a beta male from below because that is the submissive position which would make the beta male dominant. Just watch the birds in your aviaries. If a dominant cock lands on the same level as another, he will either raise himself up or fluff up part of his body so that he looks bigger than the other guy. Therefore, it is important when moving birds into a new colony to put them all in at the same time. Then, over the next three days or so, they will sort out their pecking order.