Help with Exposure

[Fotografer]

Hi! I am new to TPF, and I am hoping someone can help me with an exposure question. I photograph birds from my office window through the glass using a Canon 40D and Canon 70-200 2.8L IS lens. I am having alot of trouble getting the correct exposure when there are birds on my feeder with snow in background. The birds are always too dark. Any suggestions would be great!</p>
<p><img src="http://jmthompsonphoto.smugmug.com/photos/438518031_PtA2s-L.jpg" border="0" alt="" /></p>
<p>&nbsp;</p>
<p>1/1000</p>
<p>f3.2</p>
<p>Aperture Priority</p>
<p>ISO 320</p>
<p>Exposure +1.3 in camera</p>
<p>&nbsp;</p>
<p>If I turn down the shutter speed, I get blown highlights from the snow in the background, but the birds are better exposed. I feel like I have tried everything, but I am sure there is something I have left out!</p>
<p>&nbsp;</p>
<p>Here is another one I took the same day ~ it was 20 below F in South Dakota and the birds were just trying to stay warm!</p>
<p><img src="http://jmthompsonphoto.smugmug.com/photos/437147972_Eybhw-L.jpg" border="0" alt="" /></p>
<p>This poor guy has ice crusted around his eyes!</p>
<p>&n