Life of an ’empty’ Imperial Eagle nest

Webcams got installed at a nest of an Imperial Eagle pair for the first time in the world at the end of last year. Unfortunately, the pair started their breeding season in another nest within the territory. Nevertheless, hoping to get lucky in 2014 we left all three cameras at the nest and the one with motion-sensors recorded everything happened in the ’empty’ nest.


After browsing through hundreds of hours of footage (present collection is from the period between January and July), we discovered that the nest attracted various species of birds. Most of them tried to occupy it either because they do not build their own nest or because it was more convenient than building one. Moreover, other species just looked for some food remains, nest material to steal or visited the nest just out of curiosity.

 

Saker Falcon

The ’Turul’, sacred Falcon of our nomadic ancestors does not build a nest like other Falcon species; thus they usually occupy a nest built by other species like Eagles, Buzzards, corvids and Storks. Because of this habit we have to ensure that we save all the remaining colonies of the Rook, which went almost extinct in the past two decades (their numbers reduced by 93%!). Their protection would also be beneficial to other species, which do not build nest as the Red-footed Falcon, Kestrel, Long-eared owl and the Hobby. Before the breeding season starts Sakers visit all the potential nest sites and when they chose one they defend it even against Eagles. 


Saker at nest which was taped (Photo: MME Archive)

 

The Saker eventually did not choose the nest with cameras but probably occupied one of those nest boxes, in which 70% of the national population already breeds due to conservation efforts. 

Kerecsensólyom költőláda traverzen (Fotó: Orbán 3Zoltán).
Artificial nest-boxes, which are  a lot safer than natural twig-nests are placed
on high-voltage pylons (Photo: Zoltán Orbán).

 

Magpie

Magpies are important regulatory ‘authorities’ of the populations of Eagles. Of course, they mean no threat to grown-ups, but to the eggs if the nest is not guarded properly by the parents. Therefore, one of the most important duties of a parent Eagle is to watch and defend the nest at all times. If not done properly, even the chicks can fall victims to other raptors, besides the eggs.

Some people may think of this behaviour with revulsion , but the fact is, that in natural biological systems nest-predators play a key role in regulating populations of top-predators (also the populations of other corvid species). One should bear it in mind; those eggs and chicks make up only fraction of their diet, since they mainly feed on agricultural pest insects. As a matter of fact, contrary to what widely assumed, these species don not eradicate populations of songbirds in urban areas.

These highly intelligent and untrusting birds provided important technical feedback to researchers proving that the camera set-up was carried out well, otherwise they wouldn’t land at all. On the other hand, all the birds visiting the nest had spent some time there, which is a good sign for next year’s breeding season.

Szarka
‘Early bird’ - a Mapie checks the nest for eggs, only to find nothing yet.

 

Common Buzzard

The leading role in the history of the nest was played by the species of 2012, the Common Buzzard. They showed up regularly from January through June and let us study some secret moments of their lives. Probably of these moments,  the most intriguing was, when a third individual tried to separate the copulating pair. The pair started to renovate the nest soon after this affair, but eventually they did not nest here.

This behaviour is not strange at all, raptors usually build more than one nest in the territory. Nests may have importance in a series of ritual motions, e.g. when the female squats down, as seen on the footage; in actions like bringing and presenting nest material, because these are essential parts of courting and forming a strong relationship of a pair.

Egerészölyv.
Common Buzzard calling her mate in the ‘empty’ Imperial Eagle’s nest.

 

Egerészölyvek
Fighting Buzzards in the nest.

 

Egerészölyvek
We can follow the most exciting moments of their pair-bonding
and nest-building behaviour.

 

Starlings and Tree Sparrows

A Starling showed up for a short period of time, probably looking for a woodpecker’s hole to make its own nest in it. Poplars provide most of their nest sites in steppe habitat.

This year the Tree Sparrows were the only species breeding in the abandoned Eagle’s nest. They chose the bottom of the nest, which was perfect hiding and nesting place for them. This habit is common among Sparrows, they can be seen easily if one looks up a Stork’s nest on a pylon or a chimney.

Seregély
A Starling(up) and Tree Sparrows(lower right corner) in the Eagle’s nest.

 

Mallard

The difference between reading about Mallards laying eggs in nests of Eagles, Buzzards, Storks and seeing it live is a total far cry. Moreover, our camera also proved another fact known from the literature, the laying of eggs by more than one female in the same nest. Besides this, we can also see how they behave in each other’s presence.

Our “leading” characters, the Common Buzzards couldn’t stay away from some interaction, of course. As we can see, the incubating female Mallard has to jump off the nest when a Buzzard arrives just out of curiosity or bringing  nest material. Checking the footage, we concluded, that eventually the Mallard eggs didn’t hatch, probably due to constant harassment.

Tőkés réce
Our first guest of Mallards at the nest, ...

 

Tőkés réce
... already incubating.

 

Tőkés récék
Excitement rose to the sky, when another female showed up..

 

Tőkés réce
Hard to incubate eggs in a popular nest, like this. Being unoccupied by its
owners, the Imperial Eagle pair, the nest had attracted wide variety of birds.
Here is a Common Kestrel (it can be seen sitting on the left on a twig
at the bottom of the nest), ...

 

Egerészölyv
... and then a regular visitor, the Common Buzzard is at the nest .

 

Szarka
A Magpie takes the plunder in the absence of the female Mallard ...

 

Tőkés réce
It is not clear what is happening here, nevertheless it seems as if
a female Mallard removed a piece of eggshell from the nest.

 

Common Kestrel

Like other Falcons, the Common Kestrel don’t build a nest either. A pair of Kestrels had visited the nest for a while and entertained us with their funny-looking courting behaviour. They laid their eggs on May 8th, however, due to intolerable traffic at the nest, their breeding attempt failed, as well.

Vörös vércsék
The webcam recorded several interesting moments ...

 

Vörös vércsék
... of their courting behaviour.

 

Wood Pigeon

In the last scene, a pair of Wood Pigeons flew in the nest probbaly just being curious, because they build their own nest. One of them seemed to be very interested in the remnants of the Mallard’s nest, even though, they do not use bird feathers to their nest.

Örvös galambok
Wood Pigeons checking the Mallard’s nest being built inside the Eagle’s nest.
(Photos: MME Archive)
.

 

See the 11-minute compilation of the events between January-June, 2013 here >> (Footage: Ágnes Kiss - Természetfilm.hu Tudományos Filmműhely).  

 
 
Nature conservational aspects

Even though, our original target species did not occupy the nest, the analysis of the footage provided us with important information in relation to species and habitat conservation. Proving the importance of available nesting sites in the lowlands is probably the  number one on the list. In order to preserve these, lone trees, patches of woods and shelter-belts have to be protected or replaced in case of logging or natural tree falling. It is no coincidence that we bought ten abandoned farms in the best Eagle biotopes within the framework of the “Helicon - Conservation of the Imperial Eagles in Hungary” Life+ project coordinated by MME. By preserving and expanding wooded habitats:

  • we provide nesting sites for protected and strictly protected bird species (e.g. hole-nesting Roller);
  • and also create refuge for small wild game species in collaboration with local hunting clubs.

This latter would help us to fight the widespread misbelief, that birds of prey take a heavy toll on small wild game populations, which also led to the increase of poisoning cases. In reality, low numbers of small wild game species are the results of large-scale agricultural systems and surplus species, like the Red Fox and the Wild Boar.

Last, but not least, the study of the footage made it clear, that we have to grab every opportunity to stand up against barbarous and illegal nest shootings. Protected species fall victim to this most of the time e.g. the Saker Falcon, Red-footed Falcon, Common Kestrel, Hobby, Long-eared Owl and the Rook instead of unwanted, huntable species. 

 

Zoltán Orbán

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