Recently I was able to obtain two recordings of single squeak calls on different mornings by a bird in a local marsh. These were spontaneous calls made by a bird hidden in vegetation. The tone of these terrestrial calls is a little different from the nocturnal calls, but there is a definite similarity on the spectrograms. This seems to confirm that the presumed nocturnal calls are indeed made by migrating Least Bitterns. There is also one xeno-canto recording, by Paul Marvin, of a bird seen making this call in a flight over a marsh.
Nocturnal calls:
(early Aug, PA)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz-8mSOyONPnK1xQY5-h8Hot8N3GRPa47qD9mTi-WnqefL-wW3zZ7vHHT-MwiK0-6USWdS-o0SVaoxSSypzXwct7kqRVaWHP04Vk0OQvrdaaNg4rvg2fZBMBWNHmkCDE9iYg7cj0o0jGid/s320/LEAST+BITTERN+Elkins+Park+PA+3.24am+08072014.png)
(early October, PA)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioFJW1PbDHfSO2bQJyr9n6I4gr4c2L730pOM9IaRdUCCj-xq8TUHgIkOH2EEARbN-Z3frKMAMYuXZhsj4ORffKeLAl5HO5HGAGbBmwVMhKdRbBRxCefU3YG6Qu3XZgmhQGmCamdLaIkqaw/s320/LEAST+BITTERN+Elkins+Park+PA+4.06am+10072012.png)
(mid-Sept, PA)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0nsW2srWuV2tQQjbR4MvboEoVBjrmdDTPozKxY2-k8yOb4P_Ayx6q4GyldeHlvaOHrZtEJ6JEMXp5QGJOZIxP_teE1qUGifXa2rvHGWezXO5GymB_WH8yAVhgI9ceSq2k_XjNOMRvem5R/s320/LEAST+BITTERN+Elkins+Park+PA+4.14am+09152013.png)
Calls by terrestrial birds:
(July, PA)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwFbtXWGX-q8rX3AF9yNzD0V6AGTJcs9LFyhAhFOJRfElsf1im_oKKmvmjgNjJ50Lhy9FOxnK8vgo9yeHpAbUQk_oLqWmuVKnUKv8JhiSJRXnZ5sqwaUGzWkwu5RLr6aIaVNtb7F6TZjcA/s320/LEAST+BITTERN+Whitemarsh+Township+PA+6.52am+07312019.png)
first call (Aug, PA)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF0Cr7WSDVgw99FPqsM372onWFMDuOqZNEND3bF1etVzPcf3dYErjKcbw9OVBKeke5ketswkMrlwN_THKwpu0zLGh9whpZGXDChhDvRUl-GiNMbIWOAcbXtXypjIuxSt4UEf2JB7plB0Dg/s320/LEAST+BITTERN+Whitemarsh+Township+PA+5.32am+08132019.png)
The Xeno Canto recording (July, Fl)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE_g6aO0prhgxwxs-LraOlsoizy0fBovMLZAGxv19Qix8NZGqYEPqH3WtPLJSbQQsaXAJryclOZKKb4OBKGa2Ir04IDJZfTA9hwgIbMznrxAviqTIkQn-bC0PyBRe8uvODCI0upp5cjrn1/s320/XC326521+07082016.png)
The call is fairly distinctive, but note that some of the many varied nocturnal flight calls of the Rose-breasted Grosbeak can sound similar. Sonagram analysis can be very helpful in these cases.
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