Below is a civil registration death index for the person that may pertain to your Michael Byrne, recorded in the Athy Registration District for the September quarter of 1909. While Michael had died in May (the second, or June quarter of the year) his death wasn’t recorded by the Athy registrar until the third quarter of the year, that is, the September quarter.
The index also gives his age at death as 83 years old. If Michael had been born in 1835, he would actually have been 73 years old when he died in May. He would have turned 74 years old in September of 1909.
The death index comes from the Latter Day Saints (LDS) website at: https://www.familysearch.org/#form=advanced-records
Records are free to search at the LDS website:
Michael Byrne, "Ireland, Civil Registration Indexes, 1845-1958"
name: Michael Byrne
registration district: Athy
event type: DEATHS
registration quarter and year: Jul - Sep 1909
estimated birth year: 1826
age (at death): 83
mother's maiden name:
volume number: 3
page number: 211
digital folder number: 4201708
image number: 00352
film number: 0101604
Collection: Michael Byrne, "Ireland, Civil Registration Indexes, 1845-1958"https://familysearch.org/pal:/MM9.1.1/FRNM-KYH
Citing this Record
"Ireland, Civil Registration Indexes, 1845-1958," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/FRNM-KYH
: accessed 15 Feb 2013), Michael Byrne, 1826; citing vol. 3, p. 211, General Registry, Custom House, Dublin, Ireland; FHL microfilm 0101604.
You can order Michael Byrne’s death record from the General Register Office (GRO) located in Roscommon Town, County Roscommon. For information about ordering records from the GRO, the costs involved, and downloading application forms, go to the GRO website at: www.groireland.ie/