diff --git a/lib/index.js b/lib/index.js
index 4d0683c..5bf5968 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -361,10 +361,10 @@ const methods = Object.keys(channel).concat(Object.keys(channel.readOnly()));
 
 methods.forEach(method => {
   const bound = function(...args) {
-    const arity = method === `slice` ? 3 : channel[method].length;
+    const arity = method === `slice` ? 2 : channel[method].length;
 
-    return args.length >= arity
-      ? args[arity - 1][method](...args.slice(0, arity - 1))
+    return args.length > arity
+      ? args[arity][method](...args.slice(0, arity))
       : bound.bind(this, ...args);
   };
 
diff --git a/test/index.js b/test/index.js
index 13294e9..d88153a 100644
--- a/test/index.js
+++ b/test/index.js
@@ -129,6 +129,10 @@ describe(`Channel`, function() {
 });
 
 describe(`functional interface`, async function() {
+  it(`shift`, async function() {
+    assert.equal(await Channel.shift(Channel.of(0)), 0);
+  });
+
   describe(`slice`, function() {
     it(`full application`, async function() {
       assert.deepEqual(