How do the characters in two centuries variously understand and connect with the natural world?

How do the characters in two centuries variously understand and connect with the natural world? When Willa's phone causes "thousands of birds [to burst] from their tree skyward like a house going up in smoke," what does this potent image suggest? What about the ants that seem to inhabit the neighborhood outside the boundaries of time?

In both centuries, main characters turn to the natural world to escape their social worlds, to be refreshed and to find peace and share companionship. Both Willa, with Iano, and Thatcher, with Mary, visit the Pine Barrens.
But I notice a difference too. The 19th century characters (led by Mary) are engaged in observation, investigation, experiment, learning more about nature and adaptation; there's a sense they have of exploration, openness, freedom in nature, as well as embracing a kinship with it.

Whereas the 21st-century characters seem to cherish nature, but as curiously separate from themselves, and value almost as a thing of the past, certainly as something threatened, endangered: the path to the "Gossamer Meadow" ends in a notice that it's under repair, damaged by Hurricane Sandy. This is also what's suggested by the quote about Willa's phone sending the birds up like smoke... Human technology is literally disrupting the planet as we know it.

Thatcher, when he first meets Mary, affirms his trust in Darwin's evolutionary science, but also the "despair" that it seems to cause many people, who don't want to think of themselves as products of nature, as a part of nature, but rather as separately created beings entitled to rule over it. Their 21st century descendants reveal what has resulted from that attitude, even as evolutionary science and global warming are still contested by a vocal, politically powerful minority.

Perhaps the timeless ants are a reminder that the earth will survive, and many of its life forms will adapt and survive too, but not necessarily humans; or perhaps the ants symbolize the limitations of a highly organized "society" that is frozen in time and will not change -- especially as the ones in question, Mary tells Thatcher, are social parasites that live off of the labor of ants they have enslaved... Despots will always be with us, unless we open our minds to another way to organize society.

Agree with what JLPen77 has said above.