St. Patrick’s Day weekend proved lucky for the Dardenne brothers’ U.S. debut of The Kid With A Bike. IFC Films opened the Belgian filmmakers’ picture in 3 locations with a robust $16,300 per screen. SXSW ’11 awards-winner Natural Selection opened at the Angelika in NYC with a decent $9,201. The Duplass Bros’ Jeff Who Lives At Home bowed in 254 theaters, with a modest $3,307 average.

Co-director Mark Duplass told Deadline that their distributor Paramount Vantage spent very little on the release’s P&A debut and they hoped the film’s cast would attract audiences despite the modest marketing dollars. They remain hopeful for the weeks ahead. “We found the gamble to be good and bad,” said Duplass. “Turns out awareness of the film was low going into the weekend, but that the people who did discover the film are spreading incredibly strong word-of-mouth as evidenced by the uptick throughout the weekend. We plan to expand next weekend with a more aggressive P&A spend as well.”

The main box office story was Sony’s 21 Jump Street‘s $35 million bow, but Lionsgate’s Spanish-language Will Farrell vehicle Casa De Mi Padre had an impressive rollout for what otherwise amounted to a specialty release.

Among week 2 specialty holdovers, Roadside Attractions added 266 theaters for Friends With Kids, averaging a decent $2,344, a 26% decline from its first weekend. Lasse Hallstrom’s Salmon Fishing In The Yemen was perhaps the weekend’s most solid holdover, adding 44 screens, averaging a solid $7,339, a 45% drop from the film’s bow in 18 locations.

1. The Kid With A Bike (IFC Films) New [3 Theaters] Weekend $48K, Per Screen Average $16,300

2. Jeff Who Lives At Home (Paramount Vantage) NEW [254 Theaters] Weekend $840K, Per Screen Average $3,307

3. Natural Selection (The Cinema Guild) NEW [1 Theater] Weekend $9,201

4. Detachment (Tribeca Film) NEW [2 Theaters] Weekend $11,050, Per Screen Average $5,525

5. Seeking Justice (Anchor Bay) NEW [231 Theaters] Weekend $260K, Per Screen Average $1,126

Juan Of The Dead (Outsider Pictures) NEW [1 Theater] Weekend $12,007

Friends With Kids (Roadside Attractions) Week 2 [640 Theaters] Weekend $1.5M, Per Screen Average $2,344, Cume $4.2M

Footnote (Sony Pictures Classics) Week 2 [6 Theaters] Weekend $72K, Per Screen Average $12,018, Cume $143K

Salmon Fishing In The Yemen (CBS Films) Week 2 [62 Theaters] Weekend $455K, Per Screen Average $7,339, Cume $763K

Being Flynn (Focus Features) Week 3 [88 Theaters] Weekend $142K, Per Screen Average $1,621, Cume $262K

Boy (Paladin) Week 3 [7 Theaters] Weekend $21K, Per Screen Average $3,010, Cume $72K

Undefeated (The Weinstein Company) Week 5 [21 Theaters] Weekend $52K, Per Screen Average $2,493, Cume $330K

In Darkness (Sony Pictures Classics) Week 6 [52 Theaters] Weekend $71K, Per Screen Average $1,376, Cume $700K

W.E. (The Weinstein Company) Week 7 [18 Theaters] Weekend $25K, Per Screen Average $1,429, Cume $428K

Coriolanus (The Weinstein Company) Week 9 [21 Theaters] Weekend $31K, Per Screen Average $1,493, Cume $528K

We Need To Talk About Kevin (Oscilloscope Laboratories) Week 10 [65 Theaters] Weekend $102K, Per Screen Average $1,575, Cume $1.2M

A Separation (Sony Pictures Classics) Week 12 [282 Theaters] Weekend $510K, Per Screen Average $1,809, Cume $5.6M

The Iron Lady (The Weinstein Company) Week 12 [456 Theaters] Weekend $424K, Per Screen Average $930, Cume $28.6M

Tinker, Tailor, Soldier, Spy (Focus Features) Week 15 [86 Theaters] Weekend $95K, Per Screen Average $1,105, Cume $24.09M

The Artist (The Weinstein Company) Week 17 [1155 Theaters] Weekend $1.06M, Per Screen Average $924, Cume $42.1M

My Week With Marilyn (The Weinstein Company) Week 17 [50 Theaters] Weekend $26K, Per Screen Average $533, Cume $14.55M

The Descendants (Fox Searchlight) Week 18 [347 Theaters] Weekend $276K, Per Screen Average $795, Cume $81.9M

Related: Specialty Box Office: ‘Detachment,’ ‘Jeff Who Lives At Home,’ ‘The Kid With A Bike