Breeding Hobbys & absolute numbers of D Firetails in Callum Brae

[Julian Robinson <>]

In Callum Brae last week there were two beautifully marked immature
Hobbys. Maybe they were bred and born in Callum Brae although I haven't
visited until recently this year. Perhaps someone else saw signs of
nesting.

I conducted a small experiment while there with the aim of determining
absolute numbers of Diamond Firetails, given they are a species of
concern.  I watched a dam that they were drinking at, and in one
hour there was a consistent flow of incoming DF's and I counted 26
incoming birds.  My books say that DF's drink "several times a
day" so assuming from this that no bird drank more than once in two
hours it seems a reasonable minimum number in that area might be
2x26=52.  This would be so if they visited the dam at a constant
rate and if every bird drank every two hours, and they were not also
using any of the other dams in the vicinity.

For a maximum, you might try assuming that they only drank every 4 hours
on average and were also using one of the six other dams, (I didn't see
any but the Wed walkers saw them at a different dam a few days before)
which would give you 200.

So my guess is there are 50 - 200 Diamond Firetails in the Callum Brae at
the moment. 

Julian