Questions and Answers
Where is the nest?
In the Central Business District of Melbourne, Australia. The nestboxes are on a ledge on the edge of the building. For the welfare of the Peregrines and in the interests of managers on site, we discourage speculation about the exact location.
What's the difference between the male and female?
As with all birds of prey, the female is larger than the male. With these birds, the female appears to 'fill' the nest with her body. Both have yellow eye rings but the male's is an even circle of yellow, while the female's appear hooded - as if she's 'frowning'. The subspecies that occurs in Australia (Falco peregrinus macropus) has particularly large feet and claws (talons).
How many eggs are there?
This year (2020), there were three eggs laid with three chicks hatching on 2 October . Peregrines usually lay 3 or 4 eggs.
Are there other Peregrine Falcon sites in the city?
No. The adults won't tolerate another active nest within 2 km, minimum.
How far do they go to get their food?
This species can hunt up to 20 km from the nest site. Most hunting activity in urban settings happens within 2 km of the nest.
How old are the adult falcons?
Each of them is approximately 7 years old. At a minimum, they start to breed aged 2 to 3. We believe there has been a new male on the site since 2018, and is still there this year. It's hard to judge age accurately unless birds have been banded, which this pair are not. This is done in order to identify birds throughout their lives.
Where do they go when not sitting on the nest, catching prey or feeding the chicks?
Both the adults usually perch on 367 Collins or a neighbouring building where they have direct line of sight to the nest.
How do Peregrines feed their chicks?
They remove meat straight from the carcass of their prey. They never regurgitate food for nestlings.
What do they eat?
The falcons feed primarily on small or medium sized birds such as pigeons, cockatoos, galahs and sparrows. We've also seen them bring to the nest Rainbow Lorikeets and several small bush birds eg silvereye, Spotted Pardalote, White-plumed Honeyeater.
How many eggs do they lay?
The breeding season runs from August to November. They lay two to three eggs which are incubated by both adults for 33 days.
How much would a falcon eat in one day?
Very little 70-100g
How long before the eggs hatch?
In 2020, incubation started after the last egg was laid on Aug 29, hatching occured between 11am and 2pm (approximately) on 2 October
Why do the parents move the eggs around?
They move the eggs around to keep the temperature constant and to keep the yolk in the middle, that's where the embryo is.
Why don't the parents sit on the eggs all day?
The eggs are incubated between 37.3°C and 37,7°C. The temperature may go down a little when the falcons leave the nest for a time. The drop in temperature is mostly harmless because the chick will begin produce more and more heat itself.
How long will the chicks stay in the nest?
The chicks will fledge (fly) from the nest between five and six weeks of age. The females may take longer than this due to their extra mass.
Do the Peregrines always bring fresh kills to the nest? Do they ever stockpile food?
When they have very small young, they tend to bring fresh food for most meals. But they do stockpile food, depending on the abundance of prey.
Do the falcons have any predators? Do they face other threats?
Known predators of the eggs: brushtail possums, red foxes, tiger snakes and bush rats. These aren't an issue here. Birds or animals of any kind will be attacked if they approach the nest - this includes people.
Are these falcons banded?
No. In previous years we've held an annual press conference when we have banded nestlings, and we used to have a TV in the lobby which people would stick around and watch - according to security, an average of 20000 people per season when it was active. We have not banded the last few years.
As peregrines mate for life, what happens if one of the pair dies?
If the female dies she can be replaced within minutes. If the male dies there is a tendency for the remaining female to be more reluctant in accepting a different mate at the site. Usually within a year however she will accept a new mate.
Is it possible that one or the other of the parents were raised on this nest site (367 Collins)?
It's highly unlikely. Less than 2% of peregrines remain at the nest site in which they were hatched to breed there in future years. It's really rare to see it happen, Dr Victor Hurley has only seen it on a couple of occasions.
There's often a lot of poop in and around the nest. Does it make them sick?
This site is typical of most that Dr Hurley has seen. They are well adapted to deal with this kind of nesting environment and it is not a threat. The messiness of it shouldn't be seen as a problem for their survival.
I’d like to know how climate change is affecting Peregrine Falcons. Have there been studies on this?
Dr Hurley is unaware of any studies directly investigating climate change and peregrine falcons. The two likely impacts would be impacts at the nest, such as exposure to too much heat and or rainfall when they're trying to hatch eggs.
The second impact could be if prey populations collapse, causing a lack of food. This can happen in an area during extended drought periods They've been very fortunate to have ongoing sympathetic site management by the building owners, and this provides them with the best support they can get.
What will be the biggest challenges in the future for the Melbourne Falcons?
As to challenges, the urban adults who succeed in breeding have already overcome most of the urban challenges, such as overhead wires and mirrored windows. Other species Dr Victor Hurley works on are in much more dire straits from a conservation status than these peregrines.
Where are Peregrine Falcons found?
The Peregrine falcon is one of the most widely distributed vertebrates on the planet, found on every continent except Antarctica. Overall, 17 subspecies have been described, varying in appearance and range. Peregrine Falcons occur throughout Australia, although they are generally absent from treeless and waterless deserts and dense forests, and they seldom breed above the snowline. There are fossil records at Riversleigh in Queensland dating back to the Pleistocene, approximately 50,000 years ago.
When do eyases start getting flight feathers and how does learning to fly work from that height?
Flight feathers start from 24 to 28 days of age. You'll start to see the black flight feathers poking through the down at that stage, and from then on they spend a lot of time exercising their wing muscles.
How long do peregrines live?
On average, four years. The longest lifespan on record is 15 years.
How many times would they breed in their lifetime?
Every year after age two, assuming they have a nest and a partner. As the females get older (10 years+) they can start to increasingly lay infertile eggs.
Do you know of any cases where humans and peregrines interact or form a bond?
In the wild peregrines prefer not to be disturbed near the nest, and tend to avoid people most of the time.
How is Dr Hurley’s work funded? Can we chip in?
It's all funded personally by him and donations to the program. Currently Birdlife Australia will accept cheques or online donations via www.birdlife.org.au. Donations through the website should include a note in the comments box: 'Please direct this donation to the Victorian Peregrine Project'.
When falcons don't have chicks, how often do they hunt?
Once or twice a day, depending on the size of the bird they are able to catch.
Are there any behavioural differences observed between our city-dwellers and other, more remotely located falcons?
Not that Dr Hurley is aware of.
How do young, single falcons meet each other?
Peregrines mate for life. Generally the male locates a suitable territory with prey species and a nest reasonably close by. Then he will display and "advertise" his territory to attract a mate. They are attracted to cliffs so when dispersing and searching for a site/mate. they know where to go.
Are there any courtship rituals?
During courtship, the male provides food to the female. He must provide enough food so the female can get into condition to produce eggs. This is arduous for her, as four eggs equal roughly 25% of an adult female's bodyweight.
Do the pairs separate once their chicks have fledged and get back together the next season, or do they hang out together all year?
Bonded adult pairs hang out together for life. Both need to make sure they retain their nest and territory all year round. Australian Peregrines do not undertake annual migrations as their northern hemisphere cousins do.
What is the population of Peregrines in Victoria?
Dr Hurley estimates the Victorian Peregrine breeding population at no more than 800 - 1,000 pairs. After several decades of searching for nest sites, and building on other survey results, only 250 nests have ever been recorded.
Who gets the lucky view of the window from inside the building?
There is no window behind the nest ledge, there are some lifts and building support equipment nearby. If there was people working nearby Dr Hurley doubts they nest there.
What is it about that spot that's kept falcons nesting there for so many years? Is it because it already smells like falcons, or maybe because it's prime CBD real estate?
The building design has indented windows that create ledges, used to form gutters. Those ledges are attractive to peregrines. The nest box we've put in has a sandy substrate in it, so that attracts peregrines to use that particular ledge. We've placed it exactly where the first pair tried to breed in 91, and because they defend their territory they wouldn't be sharing house. The olfactory range of peregrines is about the same as humans, they're much more visually oriented so smell is not likely a mechanism by which they will find a nest site. To them the CBD is a canyon full of cliff faces.
Has the attention to the project made you change anything about how you go about it?
No. In previous years we've held an annual press conference when we have banded nestlings, and we used to have a TV in the lobby which people would stick around and watch - according to security an average of 20000 people per season when it was active. We have not banded the last few years.
Many watchers worry about the family sitting in the hot sun. Is that a real concern?
You'll notice the parents will shade the young from the morning sun, and all of them are doing their best to keep cool. By about 11am the building casts a shadow over the nest ledge, so during the hottest part of the day they are in total shade - this is one of the features that makes the nest attractive. I would definitely not be worried about the heat - the species has adapted to deal with this.
Do you ever handle wild falcons directly, for example, for banding?
Yes, but we are not doing so at the moment.
How long has the VPP monitored this site?
Since 1991 when they were first identified breeding there.
Is there any way of knowing whether this pair has nested here before? Are there studies of falcons in which banding was done?
There hasn't been an adult wearing bands at the site since 2011, beyond that we don't really have proof this is the same pair of a previous nesting.
How far do they range to find food? If their home range is 20-30km, does this mean there wouldn't be any other falcons nearby?
They won't nest less than 2km apart. We haven't done any radio tracking of these urban birds to know how far they hunt, but they are probably able to source prey comfortably during the breeding season within 2-3km of the nest due to the abundant and diverse range of prey in the CBD.
How is it possible for the falcons to hunt at night? Wouldn't their prey be roosting out of sight? Wouldn't the falcons depend on their sight to hunt?
The majority of the hunting is done during the day. Due to the amount of street lighting around Melbourne they can hunt after sunset, but they're unlikely to hunt throughout the night.
How do the fledglings learn to fly from such a precarious height?
As their feathers grow the young will increasingly practice stretching and flapping their wings. Also as they approach their final week in the nest the adults start to reduce the food supply. One result of this is the young actually lose weight and keep growing their flight feathers. This makes them lighter so flying is easier. In fact a fledgling will have longer wings than their parents. It's a bit like having training wheels on a toddler's bicycle.
How many breeding pairs does the Project survey in the Melbourne metro area?
In the Melbourne CBD there is only the one pair. Apart from this site we don't make it a habit of identifying the other locations, but within a 10km radius of the CBD there are 3 other sites that we have identified, and two that we suspect are also active.
Once leaving the nest do the fledglings stay with each other for a while or do they all go their separate ways?
Generally the young only stay together while dependent upon the adults at the nest site. Once they are ready to disperse each goes their own way. The females tend to disperse further than the males in order to find their own nest site. This differential dispersal behaviour is common among birds and has the effect of reducing the likelihood of inbreeding.
What predators do the falcons have when there are chicks in the nest?
Several creatures have been observed attempting to eat the eggs or chicks: red fox, brushtail possum, wedgetail eagle, tiger snake, bush rat and scrub pelican. Birds or animals of any kind will be attacked if they approach the nest - including people.
Why have falcons nested on the ledge for so many years? Is it because it already smells like falcons? Is it because it's prime CBD real estate?
The building design has indented windows that create ledges, used to form gutters. Those ledges are attractive to peregrines. The nest box has river gravel in it, so that attracts peregrines to use that particular ledge. Its been placed exactly where the first pair tried to breed in 1991, and because they defend their territory they wouldn't be sharing house. The olfactory range of peregrines is about the same as humans, they're much more visually oriented so smell is not likely a mechanism by which they will find a nest site. To them the CBD is a canyon full of cliff faces.
Has this pair nested here before? Is there any way of knowing, for example, banding studies?
There hasn't been an adult wearing bands at the site since 2011, beyond that we don't really have proof this is the same pair of a previous nesting.
How big are Peregrine Falcons?
The Peregrine Falcon (Falco peregrinus macropus) is a medium-sized raptor. Length 35-55cm and wingspan 80-105cm.
What does the name 'peregrine' mean?
The word ‘peregrine’ means ‘wandering’. Their English name and their scientific name - Falco peregrinus - refer to the migratory habits of northern hemisphere Peregrine Falcons. In Victoria, Peregrine Falcons don’t migrate.
Do the chicks compete for food?
No. There is no sibling rivalry.
How does their appearance change as they grow?
Juvenile birds are darker and browner than adults on the upperparts and buff below. After the second year, juveniles start to moult their second set of feathers and gain the horizontal bars on their underparts and the characteristic slaty-grey plumage of the adults. Adults have a charcoal black head and face and a contrasting pale cream bib on the neck and breast.
What sort of nest do Peregrines build?
Rather than building a stick nest, Peregrine Falcons usually dig a scrape on a high cliff ledge. In urban areas, they sometimes nest on artificial structures, such as window ledges of tall buildings.
How fast can they fly?
Peregrines swoop onto their prey at speeds of up to 300 km/h. They are the fastest bird and the fastest animal in the world.
Answers to these questions were collated from a variety of sources (see below) including interviews or comments from Dr Victor Hurley of the Victorian Peregrine Project.