B”H The Swifts Have Arrived . . . To Yerushalayim and the Kotel

 . . . And with them is the coming of springtime temperatures

For thousands of years, the extraordinary, tiny birds that are unfairly called “common swifts” return religiously every spring to the Western Wall adjacent to the Temple Mount in Jerusalem.

Although they don’t go there to pray, the Rabbi of the Western Wall and the Mayor of Jerusalem hold a ceremony welcoming the birds (sis in Hebrew) near evening during the last week of February. This is the time when the swifts return to their nests in the crevices of the wall to lay their eggs. The audience, which includes representatives of youth movements and the Society for the Protection of Nature, recite prayers and praise the birds.

The Prophet Jeremiah was well aware of the swifts and their behavior, as the book (Jeremiah 8:7) states: “Even the stork in the sky knows her seasons, and the turtledove, swift and crane keep the time of their coming; but My people pay no heed to the law of G–d.”

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WIKIPEDIA:  Common swifts are 16–17 cm (6.3–6.7 in) long with a wingspan of 38–40 cm (15–16 in)^[7] and entirely blackish-brown except for a small white or pale grey patch on their chins which is not visible from a distance. They have a short forked tail and very long swept-back wings that resemble a crescent or a boomerang.

Their call is a loud scream in two different tone pitches, the higher of which issues from the female. They often form 'screaming parties' during summer evenings, when 10–20 swifts will gather in flight around their nesting area, calling out and being answered by nesting swifts. Larger "screaming parties" are formed at higher altitudes, especially late in the breeding season. The purpose of these parties is uncertain, but may include ascending to sleep on the wing, while still breeding adults tend to spend the night in the nest. 

Tracking swifts at their breeding colonies using radar has revealed that individuals often occur in flocks during evening ascent and dawn descent but not during the subsequent evening descent or prior dawn ascent, suggesting that this flocking benefits the swifts via cue acquisition and information exchange between individuals or through extending social behaviour.