COVID-19 Bird Strike Update #2
It’s been a couple of months since my first attempt at tracking bird strike rates following the COVID-19 traffic downturn. At that time, viral infection rates in Europe had settled down, Australia was coming down from its second wave and even the US seemed to be cresting its second phase. On the aviation safety front, bird strike rates were showing a pretty clear sign of exceeding the 5-year average.
So how are things looking three months on?
Well, good in some ways and not so much in others. Australia is opening internally following a good run of low infection days. Air traffic is attempting a recovery but the threat of travel restrictions is constantly looming, especially as Europe deals with its second wave and the US continues to break records on the new daily infections front.
The bird strike rate trend we saw in August appears to have continued.
Reminder on Data Analysis
I have stuck with the same US data sources as they are freely available and updated regularly.
As before, I have am using the FAA Wildlife Strike Database which I have checked regularly. For traffic data, I continue to use the US Bureau of Transport Statistics.
Early on, I recognised that these traffic statistics were not the best to use as they are not the same used by more established bird strike analyses. I plan on doing some cleaning of the data in the next few months but for now, I have kept the analysis consistent and will warn readers not to quote specific strike rate values. It’s all about the trends.
I did, however, learn my lesson with the timing of bird strike reports. This time, I have included an indicator of potential growth in reported numbers for the latest three months. This line is kind of like an error bar. It exists only on the high side of the line as it is not likely that reports will be removed from the system. I used the ratio of reporting time frames I calculated in my previous post. I am looking more closely at this ratio for future analysis.
Wildlife Strikes
Raw strike numbers did not experience their usually June dip. Instead, they have trended towards pre-COVID-19 levels. The potential line is getting quite close to this line and in another month or so, the potential late report line will become clearer. Now, there has been some recovery in the US with August traffic around double what it was in May but it is still only about 50% of the same month in the previous year.
This suggests that the strike rate trend will also be up.
Wildlife Strike Rates
The trend established by May seems to have been maintained through June and July, at least. The current August rate is converging with the average a little but if further reports come in for August, the 2020 rate could blow-out to almost double the 5-year average.
Looking Deeper
It will take some time to dig deeper into this phenomenon and to discover what factors have led to this effect. At a large industry meeting back in August, there were a few anecdotes of birds becoming habituated to newly quiet aerodromes. Whether this had translated into a relative increase in strikes was not so clear.
At a more recent and smaller industry meeting, we discussed the relative concentration in operations as being a potential contributor. Some traffic numbers are showing that traffic reductions are weighted more to previous troughs or off-peak periods and that peak periods have seen much smaller reductions, if any. If these periods also match periods of bird activity, then the relative strike rate would go up.
It’s a complex network of variables that is worth a lot more analysis. Over the next couple of months, I’ll be looking at formalising these numbers a bit more - at least to make them easily comparable to similar published analyses.
But in the meantime, stay safe and healthy.
Image credit: Alan Wilson (via Wikipedia)
