by Navre » Sat Jul 07, 2018 10:16 am
I wrote this using your info to post for the volunteers at the rescue.
The solstice happened on Thursday, Jun 21 making that day, the longest of the year. From then on, the days start getting shorter and shorter until the fall equinox on Sept 21 when the day and night are of equal lengths.
For us, bird keepers, it means that the long-day species will be soon abandoning their nesting behavior and then go into molt. But, for the ones that have short-day breeders (Greys, Cockatoos, Indian Ring necks) it means that they will be going into their second ‘clutch.' Anybody who has a cockatoo that has been kept at a strict solar schedule for some time can tell you that they are back to chewing in earnest.
Strictly speaking [in a more 'traditional' sense meaning applying to all species of animals], short day breeders are the species that go into breeding condition when the days start getting shorter while long day breeders are the ones that go into condition when the days start getting longer. For example, horses are long day breeders [they give birth in the spring] and sheep are short day breeders [they give birth in the fall]. In birds, for example, you have the IRNs that go into breeding condition when there are only 10 hours of daylight because this would give them enough time to incubate and raise their young BEFORE the monsoon comes. It's the same thing with the grays, they breed during the dry season when the days are shorter and the temperature lower so they are 'done' by the time the 'wet' begins.
In the wild, short day parrots like IRNs, cockatoos and greys which, in captivity, have two breeding seasons [very early spring and late summer] have only one [the late summer one]. In captivity, food is always plentiful, and the birds are not having to deal with things like lack of water, or too much rain, etc. Because of this the birds’ bodies decide to try again once the daylight hours hits the right number for reproducing. That “right” number of hours will occur twice, on opposite sides of the solstice.
This cycle in birds is dependent on their exposure to light, and their exposure to the different wavelengths of light that occur at dusk and dawn. Their bodies adjust as the days lengthen and shorten. It’s the primary driver of their hormones. A bird kept on a human light schedule, a random light schedule, or a bird exposed to artificial light after dark, or artificial darkness during the day, can get messed up. Some people have birds who are “always” hormonal. If this is the case, you may want to look at your light management. If you like to watch Game of Thrones (is that still on?) with your bird at 11PM, you may be asking for trouble.
I know people who have birds on totally horrible light schedules who have no problem with hormones. Whatever works for you works for you, but If you have a constantly hormonal bird, a constantly depressed bird, or a plucking/screaming bird, you may want to look at light management.
If you want to see the science and research behind my rantings and ramblings about light, search for papers on “avian photoperiodism.” Don’t read them. They’re long and boring and not written for lay people. My friend Bea has done the reading and translated it into English for me.