Even Darwin Didn’t See This Coming

Robins used to be humble and small...
The harbingers of spring...
Little Robin Redbreast.
But, now, seemingly on steroids,
They've grown as big as pigeons 
And aggressive as Wrestlemania,
Squadrons of them,
Swaggering on my lawn
With the strut of a Tsar, 
Tag-teaming others,
Who'd try to sneak a seed
From my turf,
Building their nests in the most defensible places...
The high ground...
The Sun Tzus of avian warfare.
An eagle would teach them humility,
But where's one, when you need it.