HAZELHEN / HAZEL GROUSE (Bonasia bonasia) - Gélinotte des bois
Summary
A shy bird of evergreen forests with dense undergrowth, seldom seen and with extremely high-pitched calls:
Depending which book you read this species can go under either of the English names. It is undoubtedly one of the less well known grouse in Europe due to its habits and habitat. It prefers extensive undisturbed forest (not that common in modern Europe), especially if it is very moist such as in river valleys and where there is a profusion of undergrowth. Add to this its cryptic colouration, skill at hiding itself (both in trees and on the ground) and agile running ability...... get the picture ?? Not a bird you come across every day.
In Switzerland we are on the south-western edge of its distribution and, after hitting a low point in the late ‘90s, the latest census suggests that it is perhaps recovering in parts of its range. It occurs in the Jura and the Alps between 1000m - 1900m but has been recorded lower. Mulhauser (2003) studied its ecology in the Jura and estimated a population size of between 2,300 and 3,700 but this population was increasingly isolated from that in the Alps due to loss of suitable habitat in the lowlands, and was threatened by climate change and forest practises. Numbers have continued to decline in the eastern Jura.
I am fortunate that the Jura provides suitable habitat for this bird and I have seen it on several occasions but only rarely heard it vocalise. All Hazelhen songs and calls are extremely high pitched, weak, and not easy to hear. Despite this Mulhauser and Zimmerman (2003) showed that they can produce sounds which are ultrasonic to humans, and that individual males sang the same song consistently and could be identified well enough to understand aspects of their ecology.
I will relate the circumstance under which I got the recordings below as I do not pretend to understand what is going on here.
Walking along a forest track one June evening I rounded a corner and saw a Hazelhen male on the ground stretch its neck up above the herbage as they do when alarmed. It immediately ran off and then flew low into the trees, once it flew it was followed by about 5-6 others who all disappeared into dense vegetation. Clearly a family party, and I had seen a male so I assumed a female was also present as it is usually the female that carries out parental care. The most frequent sound I heard from them at first was a bubbling call as follows:
Cramp etal describe a “distraction call” of the female as something akin to this (but written words in the absence of the sounds I always find confusing), and here is a songram of those calls:
Hazelhen “alarm”
I followed the covey using their sounds down into a wet hollow and sat quietly to listen what might happen next. After 45 mins or so things seemed to have settled down but the party was still there, I frequently heard the following calls which may be song or may just be contact calls:
and I show another sonogram of these.
Hazelhen “song” or “call” ?
I was probably within 30m of the birds when I made these recordings but could not see them.
Finally at one point I heard a sound which was a sort of descending whine sound, perhaps this was part of a song or maybe just another close contact call, there were Robins and Blackbirds and Goldcrests around so there is a lot going on and I cannot get a clean sonogram, but you can clearly hear the descending "whine" at 4s, 12s, and 16s, in this edited piece:
I would love to hear from anyone who can help me to unravel all this.
