Wildlife art and illustration

For several years I have been researching gulls in the Lublin region. Here are some of the breeding birds from different parts of the Lublin region. Please note the variability.
http://gull-research.org/cachinnans/02cymay.html
http://gull-research.org/cachinnans/02cyapr.html
http://gull-research.org/cachinnans/02cyjun.html
http://gull-research.org/cachinnans/02cymar.html