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VTBIRD  November 2013

VTBIRD November 2013

Subject:

Re: Northern Harrier

From:

Jane Stein <[log in to unmask]>

Reply-To:

Vermont Birds <[log in to unmask]>

Date:

Tue, 12 Nov 2013 18:27:44 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (272 lines)

Poor you! :-(  They're so common around here, I don't bother reporting 
them to the list.

I'm pretty sure they're nesting somewhere not far from me, though I 
haven't been able to find out where, since I see usually two "red-belly" 
young cruising farm fields nearby in late summer and early fall pretty 
much every year.

Sure wish I knew where because I've never seen a courtship flight, which 
is supposed to be just spectacular.

Jane


On 11/12/2013 5:16 PM, Patti Haynes wrote:
> Winter raptors, especially Northern Harriers, may be prevalent in the
> Champlain Valley, but they are not in the Mad River Valley of Central
> Vermont... so I was surprised to find a Harrier cruising along the North
> Road in Waitsfield late this afternoon. I made no attempt to determine its
> sex ;)
>
> I have been enjoying all the information that is being passed along and
> discussed about them on VTBird. Many thanks to all!
>
> Patti
> Moretown
>
>
> On Tue, Nov 12, 2013 at 2:11 PM, Susan Fogleman <[log in to unmask]>wrote:
>
>> Maeve, Kent, Ian, Jane, et al.,
>>
>> I think the article (from 2011) Kent may have been recalling re: female
>> mimicry in male C.aeruginosus is referenced here:
>>
>> http://www.newscientist.com/article/dn21138-zoologger-the-only-crossdressing
>> -bird-of-prey.html#.UoJvh3Avri0
>>
>> The research in that case did seem to indicate advantages to the females
>> and
>> "typical" males provided by the presence of the "faux males."  Those birds
>> also had an advantage in that being 'accepted' as females, they didn't get
>> driven out of a territory the way a grey-coloured male would be.
>>
>> In a paper in the Auk from 1986, Ethan Temeles of UCDavis presents research
>> indicating a prey base relationship to gender distribution in C.cyanus.
>>
>> The Birding magazine article by Liguori and Sullivan which Maeve mentions
>> provides, IMO, quite excellent information on plumages.
>>
>> And NOW --- I will put in a plug for the HMANA Winter Raptor Survey.  As
>> Eric said, the Champlain Valley is where the action is for seeing birds of
>> prey during the winter months.  As some of you know, I have been conducting
>> a standardized survey in the Addison area for 15 years.  The data gathered
>> by such surveys across the continent can help researchers' investigations
>> in
>> any number of areas such as the effects of climate change, human impact on
>> habitats, and yes, ratios of males to females, adults to juveniles, and any
>> number of other questions.  While it is absolutely true that we cannot with
>> certainty sex Red-tails, for example, and the challenges inherit in aging
>> N.Harriers can contribute to a possibly skewed picture, some investigators
>> do feel that noting size differences (i.e. a designation of "female"
>> Red-tail means 'Large'; "male" = 'Small) or colour differences (i.e. brown
>> vs. grey Harrier) may be useful to a future research project.
>>
>> All that aside, I invite you all to consider setting up and running a
>> survey
>> route.  The more data we gather, the better, and furthermore -- it's a fun
>> way to spend a winter day!  Check
>> http://www.hmana.org/winter-raptor-survey/
>>
>> for more info.
>>
>> Here's to Harriers! And Rough-legs and Red-tails and eagles and falcons
>> and....
>>
>> Susan Fogleman
>> Campton NH
>>
>> -----Original Message-----
>> From: Vermont Birds [mailto:[log in to unmask]] On Behalf Of Maeve Kim
>> Sent: Tuesday, November 12, 2013 9:02 AM
>> To: [log in to unmask]
>> Subject: Re: [VTBIRD] Northern Harrier
>>
>> Kent and others interested in this topic - I've been hunting through old
>> birding magazines trying to find the article about male Northern Harriers
>> sometimes mimicking females in color - with no success. So I'm not sure if
>> the writer was describing birds in North America or elsewhere. I'll keep
>> looking.
>> I did find a related article that's pretty interesting, though, about color
>> variations as male harriers age:
>> https://aba.org/birding/birding452liguori.pdf
>> Maeve
>>
>>
>> On Nov 12, 2013, at 7:49 AM, Kent McFarland wrote:
>>
>>> Maeve,
>>> I thought this was just for one species in Eurasia, Circus aeruginosus.
>>> Is there evidence for that here in North America for the species that
>>> occurs here? I didn't see anything about it in the Birds of North
>> American
>>> account (revised in 2011), but maybe it was very recently discovered.
>>>
>>> They do talk about polygyny in the Birds of North America account and say
>>> it is more likely due to prey base rather than sex ratio. Our studies of
>>> Bicknell's Thrush system, which is polygynandrous (a multi-male,
>>> multi-female polygamous mating system), also pointed to prey base as a
>>> major driver.
>>>
>>> I think there are a lot of examples of polygyny in hawk-like birds:
>>> Galapagos Hawk comes to mind. Some species have been found to at least
>>> occasionally practice it: RT Hawk, Cooper's Hawk. In Europe I think
>>> something like a third of raptors are known to practice polygyny.
>>>
>>> A cool topic for sure! Thanks for bringing it up.
>>>
>>> Kent
>>>
>>> ____________________________
>>>
>>> Kent McFarland
>>> Vermont Center for Ecostudies
>>> PO Box 420 | Norwich, Vermont 05055
>>> 802.649.1431 x2
>>>
>>> [image: VCE Logo] <http://www.vtecostudies.org/>
>>> Visit Our Pages: [image:
>>>
>> Facebook]<
>> http://www.facebook.com/pages/Vermont-Center-for-Ecostudies/569309
>> 12454>
>>> [image:
>>> YouTube] <http://www.youtube.com/user/VCE14> [image:
>>> Blogger]<http://vtecostudies.blogspot.com/>
>>>
>>>
>>>
>>> On Tue, Nov 12, 2013 at 7:03 AM, Maeve Kim <[log in to unmask]>
>> wrote:
>>>
>>>> In the past few years, scientists have discovered a fascinating wrinkle
>>>> about sexual dimorphism in harriers. It used to be thought that there
>> were
>>>> many more harrier females than males. (One article I read said the ratio
>>>> was 17:1 in some parts of the world.) Everyone figured this worked for
>> the
>>>> species because harriers are the only hawk-like bird known to practice
>>>> polygyny (one male mates with several females). - But recently brown
>>>> harriers have been found that have look like females (although a bit
>>>> smaller on average) but are males. More research is being done, but the
>>>> thought now is that there have always been more harrier males than
>>>> previously recognized - that some mimic females in coloration, perhaps
>>>> allowing them to sneak into other males' territories without being
>> attacked
>>>> so they can mate with the Gray Ghosts' females.
>>>>
>>>> One of the coolest things about bird research is that it keeps
>> uncovering
>>>> more and more questions! In this case: Do female harriers accept the
>>>> odd-colored males? If so, why - when coloration is such an important
>>>> "turn-on" in so many bird species? Are there other bird species that
>> humans
>>>> sort into male and female based on color but that nature has sorted less
>>>> clearly? (Human beings love neat categories, but nature really doesn't.)
>>>>
>>>> Maeve Kim
>>>> Jericho Center
>>>>
>>>> On Nov 11, 2013, at 9:44 PM, Ian Almer Worley wrote:
>>>>
>>>>> Hi Eric,
>>>>>
>>>>> Are you saying that "gray-ghosts" can be either male or female?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Ian
>>>>> ................................
>>>>>> Hello VT Birders:
>>>>>>
>>>>>> In response/support to Jane's statement about seeing more adult male
>>>>>> Northern Harriers in winter:
>>>>>>
>>>>>> In general, mature males in good health (the breeders) tend to drift
>>>> south
>>>>>> from their breeding territories as little as possible and return to
>> them
>>>>>> quickly in late winter/spring to secure it once again.
>>>>>>
>>>>>> Given that VT sits at the northern edge of the wintering range for
>>>> Northern
>>>>>> Harriers, we end up seeing a higher percentage of "gray ghosts"
>> roughly
>>>>>> Nov-Mar.
>>>>>>
>>>>>> We observe this with Northern Harriers because they are sexual
>>>> dimorphic.
>>>>>> This holds true for other species, like Red-tailed Hawks, but there is
>>>> no
>>>>>> way to sex them so it goes unnoticed. Even if you are banding a
>>>> Red-tailed
>>>>>> Hawk, it gets reported to the banding lab as "sex unknown" due to
>>>>>> overlapping measurements.
>>>>>>
>>>>>> Wintering raptors in the Champlain Valley is one of the highlights of
>>>> being
>>>>>> a VT birder, at least from my perspective.
>>>>>>
>>>>>> Good birding,
>>>>>>
>>>>>> Eric Hynes
>>>>>> Hinesburg
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Nov 11, 2013 at 2:42 PM, Jane Stein <[log in to unmask]>
>>>> wrote:
>>>>>>
>>>>>>> Broad-winged hawks are the only raptor that all leave for the winter.
>>>> All
>>>>>>> the others are partial migrants, and our winter population here is
>>>> made up
>>>>>>> of some year-round residents and some that have moved down from
>> further
>>>>>>> north to spend the winter.
>>>>>>>
>>>>>>> Somebody with better information please correct me on this, but it's
>> my
>>>>>>> impression that with Harriers, the females and immatures tend to
>>>> migrate
>>>>>>> more, and we often end up with more adult male "grey ghosts" during
>> the
>>>>>>> winter. I recall on one trip several years ago counting 7 adult male
>>>>>>> Harriers in and around the Dead Creek area on what was probably an up
>>>> year
>>>>>>> for the vole population.
>>>>>>>
>>>>>>> Jane
>>>>>>> (Shoreham)
>>>>>>>
>>>>>>> On 11/11/2013 2:25 PM, Barbara Powers wrote:
>>>>>>>
>>>>>>>> A Northern Harrier was sitting in a tree in our field. It later took
>>>> off
>>>>>>>> to hunt. I thought they had all left for warmer climes. Nice to see
>>>> it up
>>>>>>>> close.
>>>>>>>> Barbara Powers
>>>>>>>> Manchester Center
>>>>>>>>
>>>>>>>>
>>>>>>>> -----
>>>>>>>> No virus found in this message.
>>>>>>>> Checked by AVG - www.avg.com
>>>>>>>> Version: 2014.0.4158 / Virus Database: 3629/6824 - Release Date:
>>>> 11/10/13
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2014.0.4158 / Virus Database: 3629/6827 - Release Date: 11/11/13
>

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