Date: 1/14/20 12:00 pm
From: Ed Laster <elaster523...>
Subject: Re: Unusual Behavior Update
Thanks Janine,

I was aware of the size reduction of the male testes (from the Sibley Guide to Bird Life and Behavior book) and the impact on weight, but I didn’t know about the female. By laying eggs this late I had thought it unlikely the eggs were even fertile.

I did setup a NestWatch account at Cornell and entered all the observations to documented this activity. Who knows, maybe this bird will make the BNA list of winter nesting records.

Thanks for the additional info.
Ed Laster



> On Jan 14, 2020, at 12:41 PM, Janine Perlman <jpandjf...> wrote:
>
> Thank you for the update, Ed.
>
> Many seasonally breeding animals, including most birds, have regressed/inactive gonads during non-breeding seasons. So I assumed the egg-layer wouldn't even have mated. This, from the BNA American Robin account, is interesting:
>
> At the peak of egg-laying (first brood), males testes are fully spermatogenic and females have enlarging follicles and/or have ovulated at least once. In sw. British Columbia, testes reached maximum mass throughout May; fully ripe ovarian follicles were observed most frequently in early May. Initial declines in testicular weight began in early June, although testes were fully spermatogenic throughout the month. By the latter half of June, ovulatory activity in females rapidly declined. In July, gonads of both sexes became inactive (Kemper and Taylor 1981 <https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbirdsna.org%2FSpecies-Account%2Fbna%2Fspecies%2Famerob%2Freferences%23REF64885&amp;data=02%7C01%<7CARBIRD-L...>%7Ce30590131d434ac6255a08d7992c3aaa%7C79c742c4e61c4fa5be89a3cb566a80d1%7C0%7C0%7C637146288067451413&amp;sdata=rjG%2BforSIXERV%2FEx59hcocDmfukCulxMoB39GZjDgVc%3D&amp;reserved=0>). However, there are several records of robins nesting in fall and winter (Sep: Nebraska, Tennessee, Ohio, Michigan, Illinois, Alaska, and Québec; Oct: Massachusetts and Manitoba; Nov: West Virginia; Jan: Ohio; Gardali and White 2003 <https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbirdsna.org%2FSpecies-Account%2Fbna%2Fspecies%2Famerob%2Freferences%23REF64917&amp;data=02%7C01%<7CARBIRD-L...>%7Ce30590131d434ac6255a08d7992c3aaa%7C79c742c4e61c4fa5be89a3cb566a80d1%7C0%7C0%7C637146288067451413&amp;sdata=0VIwW%2BBil6fvBy0PaxdyAMajQOz3mdXXvS3RB%2Bm16qs%3D&amp;reserved=0>). Although these constitute a small percentage of all nest records examined (< 0.1%), recent research in Missouri indicates that the majority of Oct nests were successful (8 of 10 nests fledged young; Gardali and White 2003 <https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbirdsna.org%2FSpecies-Account%2Fbna%2Fspecies%2Famerob%2Freferences%23REF64917&amp;data=02%7C01%<7CARBIRD-L...>%7Ce30590131d434ac6255a08d7992c3aaa%7C79c742c4e61c4fa5be89a3cb566a80d1%7C0%7C0%7C637146288067451413&amp;sdata=0VIwW%2BBil6fvBy0PaxdyAMajQOz3mdXXvS3RB%2Bm16qs%3D&amp;reserved=0>).
>
> Janine Perlman
> Alexander Mt., Saline Co.
>
> On 1/14/2020 9:22 AM, Ed Laster wrote:
>> The 3 Robin eggs that were reported Jan. 8, 2020 have been abandoned and the adult has not been seen in 5 days. I don’t think it is likely that the parent could have raised any chicks this time of year, even if she had been able to hatch them.
>>
>> Maybe she will be back this spring.
>>
>> Ed Laster
>> Little Rock
>


 
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