The following calendar is based on observations of the Wakefield peregrines. Whilst some elements might be specific to the two birds currently resident on Wakefield Cathedral, many of the behaviours would apply to peregrines elsewhere in lowland England.
January: The birds visit the nestbox occasionally to adjust the scrape and to perform a ledge display. During the display, the birds face each other with heads bowed. This is most likely to happen on fine days.
February: Activity at the nest increases but this is weather-dependent. The male may take prey items to the nestbox and the pair will engage in ledge displays. Watch for display flights by the male. These can be spectacular.
March: The male is very busy, impressing the female by bringing a variety of prey to the nestbox. He calls to the female and she flies to the box and takes the prey from him. She goes elsewhere to eat it, usually up on the spire. Ledge displays are becoming frequent and the female may spend extended periods in the box, possibly remaining overnight. Mating happens regularly and usually takes place high on the spire. The male flies in and lands on the female. The mating is a brief affair, lasting a few seconds. Eggs may be laid before the end of the month. They are laid at intervals of 2 to 3 days. The birds might appear to start incubating as soon as they have one egg but they are merely covering the egg(s) and incubation proper will start when the penultimate egg is laid.
April: If all goes well, the female should spend this month incubating the eggs. The male brings food for the female. The food may be left in one of the food caches that they use, such as high on the north side of the spire or on the nearby flats. The food can also be delivered to the box but the female will take it away to feed. The male takes turns incubating the eggs. The current male has the habit of doing a couple of hours early in the morning and a similar stint in late afternoon. The female always incubates overnight.
May: Eggs should hatch and the adults spend the month tending the young. Because incubation began on the laying of the penultimate egg, expect all but one of the eggs to hatch at around the same time whilst the final egg can be expected to hatch a couple of days later. Initially, the female stays nearby and the male does most of the hunting. As the youngsters grow, both birds hunt but one of them is always watching the nest, even though no adult is actually in the nestbox for much of the time.
June: The youngsters leave the nest about six weeks after hatching. Before their maiden flights, they explore the area around the box. The Wakefield birds jump up onto the wall above the box and exercise by running along the wall. When they have enough confidence, they make their first proper flight.
July: The adults work hard to feed the youngsters, which remain dependent for some weeks. Initially, a favourite place for the youngsters is on the roofs of the tower blocks. Watch for adults delivering prey to them. If you are lucky, you might observe a mid-air food pass, when one or more juveniles will chase an adult and take the prey from the adult in mid-air. The adult might drop the prey for the juveniles to catch.
August: The juveniles explore more widely and try to catch their own prey but they continue to be dependent on the adults. This is a dangerous time for the inexperienced juveniles. In cities, a major cause of death for them is collision with buildings. Sightings of juvenile peregrines at local nature reserves, such as Pugneys and St Aidan’s, can be expected.
September: Some juveniles might still be sighted but others will become independent and leave the area.
October: The juveniles have probably dispersed. This month and the remainder of the autumn and winter is an interesting time for observing the activity of the adults. As birds arrive in Britain for the winter, a range of interesting species begin to appear on the menu for the adults. These will include snipe, woodcock, redwing and fieldfare.
November: The Wakefield birds remain on their territory and continue to defend the area around the nest, repelling any intruding peregrines. The male continues to maintain one or more nest scrapes in the box and he calls to the female to draw her to the box.
December: On fine days, the male continues to visit the box and the female may also visit. At this time of year, it isn’t unusual for the birds to cache food if they catch more than they need. Their favourite store is on a piece of stonework above an arch high on the north (Bullring) side of the spire but they can also leave prey items on the crockets – the pieces of stone which protrude from the spire.