Matt, Fantastic response and very interesting from an adaptation/evolutionary perspective.
Thanks to all of you who have responded today. Anne -- Anne Baber Wallis, MHS, PhD Assistant Professor Department of Epidemiology College of Public Health University of Iowa [email protected] No woman should die giving birth. -- UNFPA www.unfpa.org/public/mothers On 12/6/11 6:23 PM, "[email protected]" <[email protected]> wrote: >Birders, > >I'll preface this response with what I am saying is by no means >scientific fact and is theory at this point. I've gathered some ideas >from ebird and other places, as well as my experience. > >To add on to AJ's great response, arctic scientists have an unexpected >theory on why so many snowies are heading south. > >As Ann said, food shortage is typically the cause for birds to be >desperate enough to fly this far for a meal. However, this year the >population level of their food source (lemmings) was at a historical >high. In nature, this usually results in highly successful reproduction >rates of the consumer. Such was the case of snowy owls, resulting in an >over-saturation of birds on winter hunting grounds. > >For the most part, it will be young birds being forced to go find new >hunting grounds, which is what we've been seeing a lot of here. There >certainly are plenty of small mammals here in Iowa during an average >winter, but these inexperienced hunters have only known lemmings, which >we do not have. Also, as Ann mentioned, they have already expended SO >much energy in making their way here, that they probably aren't at the >top of their game when they arrive. > >I spoke with raptor rehabilitator, Kay Neumann this afternoon. She >received a struggling snowy owl from the Humbolt area that ended up dying >in her care. When she weighed it, it only weighed 2lbs when it should >weigh 4lbs. > >As unfortunate as it is seeing owls die, by the theory of why we think >they are here this year, you can assume that the overall snowy owl >population won't take a hit. It will only be the best hunters of this new >crop of owls that will survive the winter and make their way back north. >So again, in a way it is food shortage, but it seems to be because there >are too many owls for the carrying capacity of their normal habitat. Not >necessarily pleasant to accept for many folks, but it is part of nature's >balancing act. > >I hope this helps and even makes you more curious to ask questions, as >well as hungry (no pun intended...maybe) to get out and watch Iowa's >birds. > >Bird on... >matt > >Matthew T. Wetrich >Naturalist, Carroll County Conservation >(712) 210-4614 >Sent from my U.S. Cellular BlackBerry® >smartphoneåy« r‰í®&îµì¨º»"‚bž -¢‹«–+-ŠØ¬¢yrjÈ(¡Ö¬™é›z»&jG¢´«v)àr§ékyÊ >&™éÝjبú+¿ÄR§b¢ë >¸¦j¼¬zWœ¶*'r§éyÿF¥µêçj׬zWœ¶*'r§ézÿDáŠÉšŠX§‚X¬¶ >+,¦‰ì¢·o+axŠ0hêçŠØh–ˆ"²Ûž*'1é›z»!Š–¯j)ZnW¨žX§y«a¶Úÿ 0ŠŒn*ݲŠàþ*.þg¦mêì >†*Z²–(¹ªÞrêëz{eÊË›±Êâmçm¢&›Š·Z±©ç{¥–+.ŠŒyÛ >W���(���n�^ʋ��(!�)���(��b�ح��'�&��� jɞ����f�z+A��b�!jyޖ���i��֭��ߢ�QK��E*�v*.����f��ǥy�b�w!jyޗ��j[^�v�zǥy�b�w!jyޗ��N�����x%��b��h��+y�������x���h�+-�I��s �����j��z���w��m����������(�����zfޮ�b��)b����.����\��� �&�v�"i��u���b�隊V�r�y�&
