What is going on with the ravens????

There are now four ravens flying around in our little valley.  Who are these two new interloper ravens and where did they come from?  We saw two ravens carrying sticks this morning.  They appear to be building a nest.  I believe they are the new pair who have moved in.  Bold and Shy already have a nest so it probably was not them carrying the sticks.   What has caused this new pair to move into the area?  Is it the real estate? The creek?  The free eggs?  This change in raven occupancy has caused a complete change in Bold's usual habits.  Bold does not come in the mornings like he used to- he comes at erratic times.  Last evening I was working at the dining room table and I looked outside.  Bold was on the deck railing trying to get my attention.  He was puffing up his feathers and bobbing his head up and down.  He definitely wanted attention and he appeared harried.  So I jumped up and put some meat scraps out on the deck railing while he waited for me.  He was in a big hurry to get the food- he stacked it up and flew off with it. 
Today I put out two eggs at about 9 AM.   Bold was just flying in when some workmen on the ridge began making a lot of noise and shouting.  Bold wheeled around and flew away.  I was sorry to see him go. It is now 1:30 PM and Bold has not returned.  Something has really upset the raven routine around here.
The grossbeaks have arrived.  We heard their beautiful song this morning.  I have not seen one but they are certainly here.   I need to get the feeder out for them with the black oil sunflower seed.  Always something to do for the wildlife population.  The goldfinches are busy eating the thistle seed and are doning their beautiful breeding plumage.  It is a beautiful day for all creatures!