Courtship and nesting
The Cape sparrow is usually monogamous, but some records of a male and two females nesting and raising young in one nest have been made in Western Cape.
It seems pairs are formed in the non-breeding flocks, but it is not known how pairs are formed, or if the pair bond for life.
Once ready to breed, newly mated pairs look for a suitable nesting site, spending mornings searching, and returning to their flock in the afternoon. Once a site has been selected, both birds begin to build their nest. Other pairs seeking a nest site join them, and in this matter a colony forms quickly.
The Cape sparrow utilises a variety of nesting sites, including holes as well as open locations. Bushes and trees, especially acacias, seem to be preferred.
Many nests may be built in a single tree.
Nests built in the open are large and untidy domed structures. Nests are built mainly of dry grass and twigs, with a soft lining of plant down. Any leaves or thorns present in a nest tree are worked into the nest. In cavity nests, the hole is simply filled with a shapeless mass of grass with a cup of soft material containing the eggs on the inside.
When the disused nests of weavers are utilised, they are simply given a
soft lining. The nest entrance is in the side, and is sometimes extended into a funnel.
This picture of mine seems to be a sparrow nest when compared to the 2nd pic off the internet.

At present we know too little about the behaviour of the Cape Sparrow to say how, when or why it lines its nest with pungent-smelling
plants, but we strongly suspect that the behaviour has benefits for chick health.
Our evidence comes not from observations of sparrow fledglings, but from information on the uses of Helichrysum species in African traditional medicine and of thyme in European traditional medicine to treat wounds and respiratory infections, and to rid the body of parasitic worms.
The medicinal powers of these herbs have nothing to do with magic or superstition, but derive from antibiotic and anti-fungal chemicals
contained in the volatile oils that give the plants their characteristic aromas.
Through trial and error over thousands of years birds and people have learned which plants have medicinal value and have come to
associate disinfectant properties with certain aromas.
If any of you do have pics of Sparrow nests, I would love you to share with us.