Is it okay for a patent attorney/patent agent to respond to elect a species upon receiving a phone call from the Examiner?

That practice should normally be avoided for two reasons:

#1.) That particular choice is for the client.  A patent attorney or patent agent ethically cannot unilaterally decide what species to elect for the client, but instead, must present the choices to the client and let the client choose which species to elect.

#2.)  It is usually better practice to have the Patent Examiner present his restriction in writing.  That not only makes the restriction response easier, but also gives the patent applicant and his agents time to analyze whether they are making the best move.