This is the "A Girl feeding a Bird in a Cage" painted by Jacob Maris. It's believed to have been created around 1867, and as you can see, it's an oil on wood painting.
The young girl depicted here is likely the same model used in another painting, "Girl Seated outside a House", which is also part of a collection somewhere else. Notice how she wears jewellery, and look carefully at what's behind her - there's a town with a church spire and some sunflowers. If you were to visit that other painting, you'd notice these elements are quite similar.
Jacob Maris was a realist painter from The Hague School, but it's tempting to see more meaning in this image of the caged bird. Perhaps it symbolizes loss of freedom or references an older style of portraiture from France, where girls were often depicted with birds.
A Girl feeding a Bird in a Cage hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.