I have been sitting at my computer writing final exams for my courses (only one week of classes left!). I have been splitting my attention, however, between the physiology of DNA replication and the activities of a pair of robins up in my backyard spruce tree.
The robins are flying in great beak-loads of wet, muddy grass and straw and are building a nest at the end of one of the middle level branches of the spruce. Last year, just below this construction site, a pair of cardinals built a nest that they eventually abandoned after it was raided by blue jays. The branch that the robins have selected seems to me to be too light and too subject to wind stresses and damage. The open location also makes the nest visible to jays (as the cardinal found out last summer). But, it's their nest and if it fails they will have two or maybe even three more tries to successfully reproduce.
A few days ago (while I was writing African ecology final exam questions) I watched a crow snapping a dry twig off of the dead, lower branches of another spruce that borders my side field. The crow took the twig, trimmed it down to a straight, foot-long piece and then flew off into the dense tree canopy at the lower end of the field. He returned in about 15 minutes and repeated the procedure several times. He was also building his nest. I plan to go down into the lower woods soon to see if I can see his chaotic piles of sticks up in the branches. It is surprising that a crow would try to nest so close to so many houses.