Counting the Odds 

Magpies are proving to be more than just noisy backyard regulars – they can actually count their rivals.  

New research from the University of Western Australia has shown that these clever birds can distinguish the number of intruders arriving nearby, a skill that could mean the difference between standing their ground or retreating. 

“Being able to distinguish how many intruders may be nearby is an important skill for animals, which then need to assess whether they could win if it came down to a fight,” said lead author Grace Blackburn in a statement. 

The study looked into whether the birds’ knack for food-based quantity discrimination carried over into social situations.  

In earlier experiments, magpies could reliably tell the difference between two and three, two and four, and even two and five pieces of cheese. This time, researchers played recordings of one, two, or three magpies calling out and measured how the birds reacted. 

The results showed that magpies grew noticeably more vigilant – standing upright and scanning their surroundings – when more callers were present.  

“It was really exciting to see that they can tell if the song is of one individual versus two or three, which is very important for them when it comes to intergroup competition,” Blackburn said. 

But the twist came when researchers compared how individuals performed across both tasks. They expected magpies that are good at spotting food quantities to also excel at judging threat levels. Instead, they found the opposite.  

“Those who performed better on the food task spent less time vigilant following the three-caller playback than magpies that weren’t as good at identifying larger quantities of food,” Blackburn explained. 

Why this negative correlation exists remains unclear.  

The team suggests that sharper magpies may simply assess threats more quickly, or that more vigilant birds might carry higher stress levels from past conflicts, which could affect their food task performance. 

“More research is required to understand the negative relationship we observed, but the fact there is any link between performance on the tasks is significant,” said Blackburn.