Dependent Young (DY) in the Garden Survey

To: "chat line" <>
Subject: Dependent Young (DY) in the Garden Survey
From: "Michael and Janette" <>
Date: Thu, 10 Mar 2005 14:35:37 +1100

A few comments to the recent messages from Martin Butterfield and Philip Veerman on the topic.


Parents with dependent young (DY) indicates the penultimate stage of raising a brood, the final one would be when the young reach full independence. Sightings of parents with DY is certainly worth recording and gives some indication of breeding success, certainly a clearer indication than nest building, incubating or carrying food to the nest. And rightly the Garden Bird Survey (GBS) has this category for breeding observations.


What I would like see is that we have two categories of ?DY? observations: (1) young raised within or in close proximity of the GBS site in question and (2) young raised well outside the GBS site in question and passing through etc.


Recording a DY event for your GBS site can be straightforward, e.g. for the resident Magpie. This species is present in the same territory all year round. Other species tend to leave the narrower boundaries of their breeding territory and move over somewhat bigger areas once they have to provide for dependent young. Many of our garden birds fall into that category. This family may appear on your block from a few blocks up or down the street. But if it is a species that you have encountered during the breeding season within or close to your GBS site, I also would have no problem to give your block as the site for the breeding event.


Other species such as the King Parrot breed well outside the suburban GBS area (although the species is in all likelihood already nesting in CNP close to town, but only in small numbers), but appear in great numbers within Canberra once the young are fledged. Parents feeding begging young are then a common sight (these observations often end up as DY breeding records on the GBS charts). These DY observations are NOT of local breeding events that can be identified with a specific GBS site. We certainly should record such observations, no problem there: they can tell us various things about the King Parrots, e.g. the length of the period young stay dependent and will beg for food, level of breeding success between years etc. However, such DY observations have to be clearly distinguished from those where the young originate from within or in close proximity to a GBS site (house block and surrounds).


Depending on the species we will find many variations between the extremes of the Magpie and the King Parrot. And in many cases a DY observation of a given species known to breed within Canberra and appearing at a GBS site, may have originated from well outside the actual GBS site where it is recorded. As I said above, I would like see us have two categories of ?DY? observations: (1) young raised within or in close proximity of the GBS site in question (and only the COG member will be able to make that decision, based on observations throughout the breeding season) and (2) young raised well outside the GBS site in question (a significant distance in the case of the King Parrot) and passing through etc.


Observations from category 1. could be plotted on a map to show the breeding distribution of a given species in urban Canberra, observations from category 2. would not be suitable for this. They can also be used to tell us something about the biology of a given species.


With the end of the current GBS year approaching, it would be great if GBS organisers could sort this out and provide relevant instructions, assuming the issue is considered important enough.


Michael Lenz

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