Memoria Press has a great variety of Science subjects to teach with your children.  We have used a few of these over the years and always enjoyed the topics we have picked.  I'm currently doing the above bird study with my littles and the resources in this curriculum are wonderful.  There are options for all ages in Memoria Press's science curriculum.  The curriculum is easy to use and very engaging to learn.  

Click here to learn more about Memoria Press - Science.