As of today, 5.29.2021, my husband saw 4 squirrels moving up in the tree branches and immediately after, a couple seed pods with leaves attached, fell to the ground.  So, we are thinking we have a few squirrels causing the tree damage.

Hi, Judi. Thanks for your question and your update.  Maples vary in the quantity of seeds they produce, from year to year and from different varieties of maple.  The time of year that seeds drop varies by variety, from spring to fall.  So, without knowing what kind of maple you have, it might be perfectly normal to have a more than usual quantity of seeds dropping at this time. Typically this happens the year after a tree has been “stressed”, for example by drought or a harsh winter.

Your observation of the squirrel activity makes sense, especially knowing that squirrels do use the maple seeds as a food source.  Great sleuthing! This might well explain the attached leaves.

Here is a link to another Ask Extension answer with more maple seed info.  https://ask2.extension.org/kb/faq.php?id=421960

Let me know if I can help further.

J.