Is there a vet in the house?

[Fotografer]

<img src="http://i43.photobucket.com/albums/e375/Exfangman/Bears/robincyst-1.jpg" border="0" alt="" /></p>
<p>Spotted at this robin decided there was better pickings on the hanging feeder</p>
<p><img src="http://i43.photobucket.com/albums/e375/Exfangman/Bears/robincyst-2.jpg" border="0" alt="" /></p>
<p>Cyst on view as it repelled an incoming great tit</p>
<p><img src="http://i43.photobucket.com/albums/e375/Exfangman/Bears/robincyst-3.jpg" border="0" alt="" /></p>
<p>That embarrassed look we all have if we have displayed our more personal parts to a medic.</p>
<p>&nbsp;</p>
<p>Any idea what the cyst is and its causes?</p>
<p>&n