Tuesday, 21 July 2020

Give a hoot

The comings and goings of our fine feathered friends are foremost in the thoughts of many locals.

Wildlife Carer Catherine highlighted the harmful effects of rodenticides on owls and other birds.

Research in WA has also shown that up to 70% of boobook owls had detectable levels of rodenticides and 18% had lethal levels... this is most likely occurring in most suburban/regional areas throughout Australia. People are using the rodenticides near where I live, and I've had a few rats dying from poison in my yard. In 2018-19 our local boobook had 3 chicks and I hate to think of them dying from these poisons. I didn't see any chicks from last year's breeding season, so this is concerning. I have also sighted a masked and barn owl here in the past.

An ABC Article from 2017 further explains the impacts of rat poisons. 

If rodenticides must be used – first generation anticoagulant rodenticides are preferred because they break down more quickly than second generation anticoagulant rodenticides

When purchasing look for active ingredients:
  • FGARs (less toxic) - Warfarin, Coumateralyl (Ratblitz)
  • SGARs (more toxic) - Brodifacoum, Bromadioline (Ratsak & Talon)
We are very fortunate to still have these birds of prey in our area and whilst we have rats they have a meal, hopefully it won’t be their last. 

Do you miss the Powerful Owls?

Local bird-O Rod Mackay shared some Powerful Owl (PO) info.

Did you know POs will tend to eat the flying foxes, which spooks them and they relocate.

It’s been happening the last few years. All the bats in Blackalls would amazingly disappear about late April when the POs came back to the area to breed (April- September).

They were also responsible for clearing the bat population out of the Botanical Gardens in Sydney a few years back.

This is the first year for about six that we have had no POs around-disappointing, but that happens. Hopefully they will be back again next year.

PO’s have bred in our community and they may be encouraged to return if we employ measures to protect these owls from disturbance or harm. There are only 6000 Powerful Owls and pairs in Australia and locally we have one of them. 

The Birdlife Australia Project has a great fact sheet for managing vegetation for powerful owls. The information below is sourced from this.

The Powerful Owl is a majestic threatened bird species that lives only along Australia’s east coast. They produce very small clutches of only one or two chicks.Protecting breeding by avoiding disturbing vegetation is vital.

The spaces owls use are made up of native and non-native plants. Broad-leaf Privet (Ligustrum lucidum), a non-native evergreen shrub and a serious environmental weed, is particularly important to owls in many of the areas they roost and nest. In fact, privet is the only tree species supporting owls in many of the urban areas where they nest in Sydney.

Privet provides shelter for the favoured prey of Powerful Owls, and it forms a vital element for owls by providing cover that lets owls roost during the day, and the cool environment owls need to persist in summer. In many cases, these owls would be unable to breed without privet. A thick shrub layer is important for new chicks, which must climb home if they have a fall when learning to fly.

Powerful Owls are creatures of habit. They like to nest in the same hollows and roost in the same trees each year, and an individual pair of owls may do this for up to 30 years. Powerful Owls are particularly sensitive to disturbance during the breeding season between April and October. Disturbance in the core part of the territory where owls are raising their chicks may cause adult owls to abandon both the chicks and the nest. Changes to the tree canopy, cutting vegetation near the nest tree, fire and tree/branch falls near the nest tree have all been documented to cause Powerful Owls to abandon nesting.

Whilst bush regeneration is sometimes the only way to restore good function in bushland, if ill-timed or too enthusiastic it can cause great harm to owls and other wildlife. When bush/land care activities are taking place in a known Powerful Owl territory the following actions are essential to protect owls:
  • Protect all hollow-bearing trees;
  • Remove woody weeds in a mosaic pattern to retain habitat for owls and small birds;
  • Avoid clearing of any vegetation that provides protected roosting sites for adults;
  • Avoid vegetation trimming that opens the canopy in riparian zones (up to 15m from creek/river); and
  • No works are to be undertaken within 100 m of an identified nesting tree or recorded observation site during the breeding season.

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