Thanks for that. Sadly I don’t have your
Pigeons and Doves in Australia. In terms of
the dramatic increase in the birds, as evidenced from GBS data. For the first 9 years of GBS (from 1981) there was almost no CP occurrence here. The increase pretty much began from year
ten as in about 1990. Then the pattern has been of a consistent increase, with no breaks in the rise, to now a relative stable state. Occurrences on previous decades were, it appears localised and of short duration. Just using GBS, there wasn’t any change
in systematic observations by local birdwatchers in those first ten years compared to the years since. The observer effort and the survey protocol had been relatively consistent for all the years. This is the 21 year abundance graph. There really isn’t another
species showing the same change in abundance. The last ABR gives the A value for the year as 4.48, so the increase has clearly continued since the A value of about 2.3 (showing in the graph) in year 21.
It is interesting to see you give the name as Crested Bronzewings and I have wondered why that name is not normally used.
.
From: joseph forshaw [
Sent: Monday, 8 March, 2021 5:16 PM
To: John Layton; 'Philip Veerman'; 'Canberra birds'
Subject: RE: [Canberrabirds] Fatalities among Crested Pigeon young.
In my
Pigeons and Doves in Australia, I document the spread of Crested Bronzewings in the Canberra district, pointing out that in his
Pigeons and Doves of Australia (1982) Harry Frith notes that there was a local population here in the mid 1950s. They certainly were here when I came to Canberra at the end of 1959, but were localised in the vicinity of the racecourse and adjoining stables.
Obviously there was localised breeding at that time. The first apparent increase occurred in the mid to late 1960s, when they were seen more widely in western outskirts of the city, and then a marked increase occurred in the early 1980s, which really started
the rapid increase in both dispersal and numbers. I suggest that dating their increase to 1990 reflects the commencement of systematic observations by local birdwatchers rather than any dramatic increase in the birds.
Kind regards,
Joe Forshaw
From: Canberrabirds <>
On Behalf Of John Layton
Sent: Monday, 8 March 2021 2:03 PM
To: 'Philip Veerman' <>; 'Canberra birds' <>
Subject: Re: [Canberrabirds] Fatalities among Crested Pigeon young.
Philip,
Just by way of interest (and you’re probably aware of this) I seem to remember reading that there has been an influx of Crested Pigeons to our area at least once during the former half of the 20th Century, but it appears that
a breeding population didn’t establish for whatever reasons until c.1990.
John Layton
From: Canberrabirds
On Behalf Of Philip Veerman
Sent: Monday, 8 March 2021 11:33 AM
To: 'Canberra birds'
Subject: [Canberrabirds] Fatalities among Crested Pigeon young.
Indeed that raises extra thoughts. It is only very recently that Crested Pigeons have inhabited this environment. The species was non-occurring and then rare
here until 1990 (GBS Report, as below), and the first breeding of the GBS was in year 8. Also historically the Pied Currawong was not a common breeder in our region, most migrating into the high country to breed. Just on geography, the (historical) natural
range of the Pied Currawong is also mostly exclusive of the (historical) natural range of the Crested Pigeons. Our habitat changes have brought them together. On that basis, the high predation interaction of these two is surely a very recent phenomenon. The
prey species has had little time to form any defences to the predator. They just breed a lot, which is not of itself odd for a dry country adapted species that presumably breeds when times are good, now finding itself in an environment of perpetual abundance.
Philip
Crested Pigeon Ocyphaps lophotes
This species has a broad Australian distribution, mostly occurring in the dry to semi-dry areas. It has spread considerably in recent years. It is conspicuous and approachable. It tends to occur in small groups on open
short grass where it feeds on seed. It will readily come into suburban gardens. Numbers vary only slightly through the year, from a minimum in November, then rises steadily to a peak in May and June. This may reflect the main breeding activity in Sept-Mar,
with a steady increase in the population as young birds enter the population up to May, followed by a decline as mortality or dispersion impacts and the population returns to a more stable level. Its long-term change may even be represented in the monthly
histogram. The fact that June abundance is higher than that of July (eleven months earlier), reflects the steady population increase of the species. Numbers have risen dramatically. There were only three observations of a total of four birds during the first
five years. For the first nine years there were 17 records from northern Canberra starting in Year 3, with 3 records from central Canberra starting in Year 1 and 12 records from southern Canberra starting in Year 6. So it took about six years for the species
to spread from its initial population in the northern and central suburbs to southern Canberra. The almost exponential rise took off in Year 10. From about Year 11 onwards the distribution has been generally uniform, though slightly more prevalent in northern
and southern suburbs than central ones. In Year 21 it ranked as the 13th most common species and occurred at 95% of sites. It appears to be stable and evening off now. Breeding records have increased dramatically, the first in Year 8, the next in Year 13,
then several each year. Few complete breeding events noted and the breeding period appears to be very broad with display at almost any time and actual activity at nest from late September to late March.
Graphs on page: 93, Rank: 45, Breeding Rank: 19, A = 0.59508, F = 39.91%, W = 33.7, R = 20.986%, G = 2.84.
From: Canberrabirds
On Behalf Of Philip Veerman
Sent: Monday, 8 March, 2021 11:02 AM
To: 'Canberra birds'
Subject: Re: [Canberrabirds] Fatalities among Crested Pigeon young.
They are a frequent prey item of Pied Currawongs and no doubt other predators.
