Scientists studied the vernal window — transition period from winter to the growing season. They found that warmer winters with less snow resulted in a longer lag time between spring events and a more protracted vernal window. This change in the spring timetable has ecological, social and economic consequences — for agriculture, fisheries and tourism. As the ice melts earlier, the birds don't return, causing a delay, or lengthening in springtime ecological events.
With reference to the above passage, the following assumptions have been made :
1. Global warming is causing spring to come early and for longer durations.
2. Early spring and longer period of spring is not good for bird populations.
Which of the above assumptions is/are correct?