Prey items over the years

Xavier brought the first courtship gift on Sunday (a red-rumped parrot). So it might be timely to look at prey bringing over the years (August 2012- April 2024).

M1 = Beau (2012-2015) M2 = Bula (2015-6) M3 = Xavier (2016-2024). F1 – Swift (2012-2o15); F2 = Diamond (2015-2024). AU = Adult unknown

This graph shows the average number of prey items taken each month by each falcon and brought to the nest box. Males are shown in brown; females in green; and unknown in grey. The unknown represent prey brought to the box by the female, but may have been caught by the male and passed to her. There were few prey from December to June, so the means have been summed.

Standard deviations represent the variability between each year. The figures have been adjusted to account for time periods where no observations were made. I’ve also removed repeat offerings eg where a male repeatedly brings starlings or other birds to the box, but these prey are ignored by the female.

Observations:

Prey is brought in every month, but does not really ramp until July. Interestingly, although male captures outnumber females in the breeding season, this does not appear to be the case from December to June.

The differences between males are less obvious than between the females, where F2 brought over three times the prey than F1 in October and over double in November. This can partly be explained by the difference in nestling numbers, (F1 hatched a mean of 1.3 and fledged 1.1; and F2 hatched 2.1 and fledged 1.7). It may also be that F2 was lame in her last year and had to leave much of the hunting to her mates.

You will note also that the females brought in very little prey in September, the main month for incubating (which the female does most of ) and the greatest effort by both sexes is during October and November when there are mouths to feed.

In August there is a strong rise in numbers. This is the period when the males are bringing courtship gifts to their partners and to provide evidence of their hunting prowess. There is evidence in the literature of reverse offerings by the female, but this would not appear to be a frequent occurrence at this site.