Septimus & Clarissa - Birds in a cage?

We were told in class on Monday to closely watch the manner in which Septimus Warren Smith and Clarissa Dalloway's lives parallel each other.

I had decided to follow the theme of birds in the text, and found that the first hints at the relation between Clarissa and Septimus is subtly pointed out in their physical descriptions; both characters are described as bird-like.
When Clarissa is heading out to buy flowers, Scrope Purvis notes that she is "perched" on the side of the road, and has "a touch of the bird about her, of the jay, blue-green, light, vivacious," (4).

Septimus is not described as a bird in such detail as Clarissa, but his brief physical description on page 14 notes that he is "beak-nosed."

The reader slowly begins to discover that these characters feel unhappy with and trapped in their everyday lives (Septimus more obviously so). Perhaps their bird-like descriptions metaphorically represent their desire to fly away? Or maybe these descriptions are meant to hint that Septimus and Clarissa are trapped, like pet birds, in the cage of society?

I have no doubts that Woolf described these characters as bird-like on purpose, and am interested to see how if the theme continues through the rest of the novel.