We have Common Grackles nesting on top of a Robin nest under the eaves of
our barn. No sooner had the Robin chicks fledged than the Grackles moved
in. They enlarged and raised the level of the nest. One bird seems to be
staying on the nest throughout the day. I would like to know if this is
unusual behavior for Grackles. I thought they nested primarily in
conifers. Any ideas?