How Anti-Bird Spikes Became De Rigueur Nesting Material Amongst Corvids

Photo of an anti-bird spike nest by Auke-Florian Hiemstra

 

 

No sooner had I published a post on urban birds using rubbish to build their nests - click here - than I came across several news reports on a Dutch study in to how super-intelligent crows and magpies are ironically incorporating technology designed to deter them from making a home into their nest designs, something that has astonished even those who have long admired corvids for their cognitive skills.

 

Apparently, nests recovered from trees in Rotterdam and Antwerp, were found to be constructed almost entirely from strips of those long metal spikes often attached to buildings in order to prevent our feathered friends from nesting, or even finding a place to perch for a few moments. Whilst the crows seem to have simply utilised the spikes as a sturdy construction material, the magpies may have appreciated their intended purpose, as they positioned most of the spikes on the nest's roof where they could deter predators, including other birds and mammals.

 

Interestingly, rather than merely finding old strips of anti-bird spikes at rubbish dumps, a researcher claims that crows and magpies may even be removing the metal strips directly from buildings in an act of avian vandalism.

 

As Dewey Finn would say: That is so punk rock!

 

 

Note: for more on this story visit the BBC News Science & Environment page: click here. 

 

 

A Bird in the Bush is Better Than a Bird Forced to Nest in Rubbish

The bird a nest, the spider a web, man pollution

 

 

There has been increasing concern over recent years about the fact that more and more species of birds are using rubbish as nest building material [1].

 

Obviously, one of the main reasons for this is necessity; uncontrolled human population growth and the associated spread of urban landscapes results in the destruction of natural spaces and the subsequent loss of natural nest building materials [2] and so birds - like other animals - have to adapt to survive.  

 

Unfortunately, not all bird species will be able to adapt to living in limited numbers in small isolated areas surrounded by people, cars, buildings, bright lights, etc. A big city lifestyle amongst the garbage isn't for everyone.  

 

But some birds are at least giving it a go and they constitute one of the most common groups of urban animals: 

 

"Their ability to fly allows them to move quickly between places to find refuge, food, or water inside cities. Additionally, several bird species are well adapted to urban areas because of their generalized diets (in other words, they can tolerate the majority of food resources available), large brains (allowing them to solve problems and use new resources), non-specific requirements for nesting places (can nest in the majority of available places), and small sizes (allowing larger populations to survive on small amounts of resources)." [3] 

 

However, whether using a diversity of waste materials - including plastic, wood, metal and rubber - as nesting material will prove to be beneficial or harmful to their survival in the long term remains to be seen. I suspect the latter [4]. For whilst there do seem to be some advantages to a nest constructed from artificial materials - for example, the nicotine found in fag ends is a known repellent against some parasitic insects - there are several negative consequences identified by researchers:    

 

"For example, one negative effect of the use of garbage for nest building could be an increase in the nest temperature when birds use plastic bags pieces, a situation that could negatively affect an egg's embryo development. Another negative effect may be an increase in nest predation if, by being more conspicuous, artificial materials make nests more easily detectable by visual predators. It is also possible to expect a decrease in chicks' survival because plastic or nylon ropes may attach and tangle around chicks in the nest, causing mortality." [5]

 

Let's just say that it isn't yet certain what the consequences will be of this new behaviour. But, having said that, I think we can agree that it makes the heart sink to read about baby birds reared amongst garbage and eating particles of microplastic.

 

 

Notes

 

[1] Such behaviour isn't new - indeed, it has been observed since the early 19th-century - but it is rapidly increasing as the natural environment becomes ever-more shaped (and polluted) by humanity.

 

[2] As two researchers in the field of urban ecology write: "The reduction in abundance of natural materials for nest building is probably the force incentivizing species to use artificial materials, which are becoming more, not less, available as human activities increase." 

      See Josué Corrales and Luis Sandoval, 'Our Garbage, Their Homes: Artificial Material as Nesting Material' (December 2016). To read this text online, visit The Nature of Cities website: click here.

 

[3] Ibid.

 

[4] For a report by Anjit Naranjan in The Guardian (10 July 2023) on a newly published European study concerned with the safety of chicks being reared in nests constructed from rubbish, click here. 

[5] Josué Corrales and Luis Sandoval, 'Our Garbage, Their Homes: Artificial Material as Nesting Material', op. cit. 

 

 

For a follow up post to this one on crows and magpies ingeniously using human technology (anti-bird spikes) to protect their nests, click here.