Due to a formula error and me not having any idea how much small fish weigh, please ignore the paragraph in my previous message about the weight of the prey consumed as it is incorrect. I will clarify the estimate when I have educated myself
more on the weight of small fish and I am happy with the numbers.
Steve
From:
Wallaces <>
Sent: Thursday, March 21, 2024 4:03 PM
To: Canberra birds <>
Subject: Australian Little Bittern 2024 compared to 2012
The extended time the female Australian Little Bittern spent feeding in front of Cygnus hide on 19 March 2024 allowed the capture of enough video to compare it
to the behaviour of a female recorded on 18 October and 22 November 2012 (see
Canberra Bird Notes June 2013). I have not completed the comparison but already the analysis is showing some significant differences in the intensity of feeding. While the percentage of strikes that resulted in the capture of a prey item was similar (70%
in 2012, 71% in 2024), the rate of strikes was more than double in 2024 (26 per hour in 2012, 58 per hour in 2024). This increase in strike rate may have to do with a higher density of prey, which is indicated by the rate of movement of the bird in 2024 being
considerably less (299, 134 steps per hour).
Preliminary estimates of the weight of the 34 prey items taken in 2024 indicate that they represent nearly half the weight of the average weight of the species
(83.6g HANZAB). This estimate may change as it is based on the prey being weatherloach, which is yet to be confirmed.
I will write an article for CBN when I have finished the analysis but I thought these differences were worth a short note to the chatline.
Steve
|
|
Oct/Nov 2012
|
Mar 2024
|
|
Video analysed (minutes)
|
62
|
50
|
|
Strikes per hour
|
26
|
58
|
|
Successful strikes per hour
|
18
|
41
|
|
Percent of successful strikes
|
70
|
71
|
|
Steps
|
309
|
114
|
|
Steps per hour
|
299
|
137
|
