An unscientific peek into how Oahu’s electorate voted in the Honolulu mayor’s race shows Mayor Kirk Caldwell and former U.S. Rep. Charles Djou each faring well in some regions while in need of work in other communities as they head for their Nov. 8 showdown.

Caldwell relied on solid support through the midsection of the island — from Salt Lake to Wahiawa — to secure his first-place finish in Saturday’s primary election. Djou, meanwhile, counted on his home base of East Honolulu and Kailua to bolster him but also found somewhat surprising support in areas like Kalihi and the Waianae Coast where Democrats have traditionally done well.

Caldwell is a card-carrying Democrat while Djou is a Republican.

In the islandwide tallies Caldwell grabbed 44.6 percent of the 166,002 votes cast while Djou captured 43.7 percent of the votes in a close, second-place finish.

Precinct breakdowns showed Caldwell winning a majority of the votes within the borders of 18 Oahu state House of Representatives districts while Djou carried the day in 17 House districts. Going further into the weeds, Caldwell was first in 78 Oahu precincts while Djou was tops in 74 of them, with one additional precinct — a mail-in-only section of Kunia — a tie since no one voted in it.

That count, however, belies the fact that Caldwell won more of the precincts with the larger turnouts while more of Djou’s support came from smaller precincts.

For instance, Caldwell’s largest margins of victory were in House District 33 (Halawa-Aiea-Newtown), where he won by 783 votes; District 34 (Pearl City- Waimalu-Pacific Palisades), where he was ahead of Djou by 777 votes; and District 37 (Mililani-Waipio-Waikele), which he took by 780 votes.

Djou took some districts decisively as well, however. He won District 17 (Kalama Valley-Queen’s Gate-Hawaii Kai) by 721 votes and District 18 (Hahaione Valley- Aina Haina-Kahala) by 747 votes.

There were also a number of districts where Caldwell and Djou finished within 50 votes of each other. Djou bested Caldwell in District 22 (Waikiki-Ala Moana-Kakaako) by only 10 votes, District 27 (Nuuanu-Liliha- Alewa Heights) by 40 votes and District 43 (Kalaeloa-Ko Olina-Maili) by 30 votes.

Similarly, the incumbent beat Djou in District 31 (Fort Shafter-Moanalua Gardens-Aliamanu) by seven votes and District 46 (Wahiawa-Whitmore-Poamoho) by 66 votes.

Some traditionally Democratic regions where Djou showed strength were Districts 28 (Kamehameha Heights-Kalihi Valley), 29 (Chinatown-Iwilei-Kalihi) and 44 (Waianae-Makaha-Makua).

A question being asked the day after the primary is where the 15,539 votes that former Mayor Peter Carlisle received will go. Carlisle was eliminated from contention after finishing third in the field of 11. The data offer no clue about the answer, however, since Carlisle finished third in all Oahu precincts and by about the same margins.

Neighboring communities showed stark differences in some parts of the island. Djou won District 50 (Kailua-Kaneohe) handily while Caldwell won District 49 (Kaneohe-Maunawili-Kailua). In West Oahu, Caldwell won District 41 (Ewa Villages-Ocean Pointe-Ewa Beach) while Djou took District 40 (Ewa Beach-Iroquois Point).

Caldwell, surprisingly, did well in areas where rail construction has caused the most headaches, winning in Waipahu and Pearl City-Aiea districts.

Caldwell is considered the contentious $8 billion rail project’s biggest supporter, while Djou has been among its staunchest critics.