The year that myxomatosis became widespread in the UK, my friend and I noticed that waterhens, abundant in our area, hadn't laid any eggs that spring. Nests were built, but no eggs laid.
We concluded that myxomatosis was to blame, since no other factors had changed from previous years.
No-one in the scientific or naturalist community seemed to notice, apart from one small mention in a nature magazine that generated no comments and wasn't followed up.
In the following year, eggs were laid, but in much reduced amounts.
To this day I'm still curious to know whether there could have been a link with the disease.