Mourning Doves (not morning)

I woke up unusually early and couldn't fall back to sleep, so I went to a local park to sit by the water and see what I could see.  There were relatively clear skies this morning, and it was a little cooler than room temperature with a nice breeze blowing.  Memorial Park in Pottstown, PA is partially classified as a Palustrine Forest (in this case, a Sycamore-dominated floodplain).  A big portion of the park, however, has been turned into recreation areas--baseball fields, BMX track, dog park, etc.  I was sitting on a bench along the riparian zone of Manatawny Creek.  By about 6:45 a.m., I was watching a Mallard Duck couple drift along and heard noise behind me.  When I turned around, I saw a few of what I thought were pigeons because of the way they moved.  That head-bobbing motion when they walk as if they are even seeking food in the air makes me think of being in the city and hoping I don't get pooped on.  They were pecking around in the grass just at the edge of an asphalt walking path (perhaps another reason I immediately thought--pigeons!).  I am incredibly new to this whole world of bird watching and identification, so I pulled out the field guide I bought myself: National Geographic (cited below).

I quick-referenced "pigeon."  No way.  The coloration was totally wrong, although the body shape was a bit similar.  So I turned the page and saw doves... this body shape was exactly what I was seeing: short legs, a bit plump to my eyes but with a more distinguishable neck than the thrushes and sparrows I have observed lately, small head, dull gray-brown in color with black speckles on its rump/scapular area and darker primary feathers, with a long tail that came to a point at the end.  Mourning doves.  I have heard the name, but, in my ignorance, thought they were birds that came out in the morning, not named because of their sad-sounding call.  I watched them collect seeds for a while, feeling like a busy-body and wondering if they minded someone watching them eat.

Dunn, J. L. (2017). Field guide to the birds of north america 7th edition.
     National Geographic Society.