An obvious advantage of birding with a group is that more eyes spot more birds (with diminishing returns certainly). The advantage of birding by yourself is the birds have a harder time spotting you. When I'm birding by myself I tend to move fairly slowly (which used to drive Ginger nuts when she would walk trails with me), but it paid off at lunchtime in Savegre when I found a feeding flock, worked my way in front of it, and let the birds come to me.
As per usual, Sooty-capped Bush-tanagers dominated the flock
Their cousin the (at least in the highlands somewhat less-) Common Bush-tanager joined them
No mixed flock at this elevation would lack a Collared Redstart
This Ruddy-capped Nightengale-thrush was on the way back to the cabins, appearing at my feet